xref: /llvm-project/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp (revision dcc04e09cf6e36c6d2c47057a8f201f2c0784c69)
1 //=== MallocChecker.cpp - A malloc/free checker -------------------*- C++ -*--//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines a variety of memory management related checkers, such as
10 // leak, double free, and use-after-free.
11 //
12 // The following checkers are defined here:
13 //
14 //   * MallocChecker
15 //       Despite its name, it models all sorts of memory allocations and
16 //       de- or reallocation, including but not limited to malloc, free,
17 //       relloc, new, delete. It also reports on a variety of memory misuse
18 //       errors.
19 //       Many other checkers interact very closely with this checker, in fact,
20 //       most are merely options to this one. Other checkers may register
21 //       MallocChecker, but do not enable MallocChecker's reports (more details
22 //       to follow around its field, ChecksEnabled).
23 //       It also has a boolean "Optimistic" checker option, which if set to true
24 //       will cause the checker to model user defined memory management related
25 //       functions annotated via the attribute ownership_takes, ownership_holds
26 //       and ownership_returns.
27 //
28 //   * NewDeleteChecker
29 //       Enables the modeling of new, new[], delete, delete[] in MallocChecker,
30 //       and checks for related double-free and use-after-free errors.
31 //
32 //   * NewDeleteLeaksChecker
33 //       Checks for leaks related to new, new[], delete, delete[].
34 //       Depends on NewDeleteChecker.
35 //
36 //   * MismatchedDeallocatorChecker
37 //       Enables checking whether memory is deallocated with the correspending
38 //       allocation function in MallocChecker, such as malloc() allocated
39 //       regions are only freed by free(), new by delete, new[] by delete[].
40 //
41 //  InnerPointerChecker interacts very closely with MallocChecker, but unlike
42 //  the above checkers, it has it's own file, hence the many InnerPointerChecker
43 //  related headers and non-static functions.
44 //
45 //===----------------------------------------------------------------------===//
46 
47 #include "AllocationState.h"
48 #include "InterCheckerAPI.h"
49 #include "clang/AST/Attr.h"
50 #include "clang/AST/ParentMap.h"
51 #include "clang/Basic/SourceManager.h"
52 #include "clang/Basic/TargetInfo.h"
53 #include "clang/Lex/Lexer.h"
54 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
55 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
56 #include "clang/StaticAnalyzer/Core/BugReporter/CommonBugCategories.h"
57 #include "clang/StaticAnalyzer/Core/Checker.h"
58 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
59 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
60 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
61 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerHelpers.h"
62 #include "clang/StaticAnalyzer/Core/PathSensitive/DynamicSize.h"
63 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
64 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
65 #include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
66 #include "llvm/ADT/STLExtras.h"
67 #include "llvm/ADT/SmallString.h"
68 #include "llvm/ADT/StringExtras.h"
69 #include "llvm/Support/ErrorHandling.h"
70 #include <climits>
71 #include <utility>
72 
73 using namespace clang;
74 using namespace ento;
75 
76 //===----------------------------------------------------------------------===//
77 // The types of allocation we're modeling. This is used to check whether a
78 // dynamically allocated object is deallocated with the correct function, like
79 // not using operator delete on an object created by malloc(), or alloca regions
80 // aren't ever deallocated manually.
81 //===----------------------------------------------------------------------===//
82 
83 namespace {
84 
85 // Used to check correspondence between allocators and deallocators.
86 enum AllocationFamily {
87   AF_None,
88   AF_Malloc,
89   AF_CXXNew,
90   AF_CXXNewArray,
91   AF_IfNameIndex,
92   AF_Alloca,
93   AF_InnerBuffer
94 };
95 
96 struct MemFunctionInfoTy;
97 
98 } // end of anonymous namespace
99 
100 /// Print names of allocators and deallocators.
101 ///
102 /// \returns true on success.
103 static bool printMemFnName(raw_ostream &os, CheckerContext &C, const Expr *E);
104 
105 /// Print expected name of an allocator based on the deallocator's family
106 /// derived from the DeallocExpr.
107 static void printExpectedAllocName(raw_ostream &os, AllocationFamily Family);
108 
109 /// Print expected name of a deallocator based on the allocator's
110 /// family.
111 static void printExpectedDeallocName(raw_ostream &os, AllocationFamily Family);
112 
113 //===----------------------------------------------------------------------===//
114 // The state of a symbol, in terms of memory management.
115 //===----------------------------------------------------------------------===//
116 
117 namespace {
118 
119 class RefState {
120   enum Kind {
121     // Reference to allocated memory.
122     Allocated,
123     // Reference to zero-allocated memory.
124     AllocatedOfSizeZero,
125     // Reference to released/freed memory.
126     Released,
127     // The responsibility for freeing resources has transferred from
128     // this reference. A relinquished symbol should not be freed.
129     Relinquished,
130     // We are no longer guaranteed to have observed all manipulations
131     // of this pointer/memory. For example, it could have been
132     // passed as a parameter to an opaque function.
133     Escaped
134   };
135 
136   const Stmt *S;
137 
138   Kind K;
139   AllocationFamily Family;
140 
141   RefState(Kind k, const Stmt *s, AllocationFamily family)
142       : S(s), K(k), Family(family) {
143     assert(family != AF_None);
144   }
145 
146 public:
147   bool isAllocated() const { return K == Allocated; }
148   bool isAllocatedOfSizeZero() const { return K == AllocatedOfSizeZero; }
149   bool isReleased() const { return K == Released; }
150   bool isRelinquished() const { return K == Relinquished; }
151   bool isEscaped() const { return K == Escaped; }
152   AllocationFamily getAllocationFamily() const { return Family; }
153   const Stmt *getStmt() const { return S; }
154 
155   bool operator==(const RefState &X) const {
156     return K == X.K && S == X.S && Family == X.Family;
157   }
158 
159   static RefState getAllocated(AllocationFamily family, const Stmt *s) {
160     return RefState(Allocated, s, family);
161   }
162   static RefState getAllocatedOfSizeZero(const RefState *RS) {
163     return RefState(AllocatedOfSizeZero, RS->getStmt(),
164                     RS->getAllocationFamily());
165   }
166   static RefState getReleased(AllocationFamily family, const Stmt *s) {
167     return RefState(Released, s, family);
168   }
169   static RefState getRelinquished(AllocationFamily family, const Stmt *s) {
170     return RefState(Relinquished, s, family);
171   }
172   static RefState getEscaped(const RefState *RS) {
173     return RefState(Escaped, RS->getStmt(), RS->getAllocationFamily());
174   }
175 
176   void Profile(llvm::FoldingSetNodeID &ID) const {
177     ID.AddInteger(K);
178     ID.AddPointer(S);
179     ID.AddInteger(Family);
180   }
181 
182   LLVM_DUMP_METHOD void dump(raw_ostream &OS) const {
183     switch (K) {
184 #define CASE(ID) case ID: OS << #ID; break;
185     CASE(Allocated)
186     CASE(AllocatedOfSizeZero)
187     CASE(Released)
188     CASE(Relinquished)
189     CASE(Escaped)
190     }
191   }
192 
193   LLVM_DUMP_METHOD void dump() const { dump(llvm::errs()); }
194 };
195 
196 } // end of anonymous namespace
197 
198 REGISTER_MAP_WITH_PROGRAMSTATE(RegionState, SymbolRef, RefState)
199 
200 /// Check if the memory associated with this symbol was released.
201 static bool isReleased(SymbolRef Sym, CheckerContext &C);
202 
203 /// Update the RefState to reflect the new memory allocation.
204 /// The optional \p RetVal parameter specifies the newly allocated pointer
205 /// value; if unspecified, the value of expression \p E is used.
206 static ProgramStateRef MallocUpdateRefState(CheckerContext &C, const Expr *E,
207                                             ProgramStateRef State,
208                                             AllocationFamily Family,
209                                             Optional<SVal> RetVal = None);
210 
211 //===----------------------------------------------------------------------===//
212 // The modeling of memory reallocation.
213 //
214 // The terminology 'toPtr' and 'fromPtr' will be used:
215 //   toPtr = realloc(fromPtr, 20);
216 //===----------------------------------------------------------------------===//
217 
218 REGISTER_SET_WITH_PROGRAMSTATE(ReallocSizeZeroSymbols, SymbolRef)
219 
220 namespace {
221 
222 /// The state of 'fromPtr' after reallocation is known to have failed.
223 enum OwnershipAfterReallocKind {
224   // The symbol needs to be freed (e.g.: realloc)
225   OAR_ToBeFreedAfterFailure,
226   // The symbol has been freed (e.g.: reallocf)
227   OAR_FreeOnFailure,
228   // The symbol doesn't have to freed (e.g.: we aren't sure if, how and where
229   // 'fromPtr' was allocated:
230   //    void Haha(int *ptr) {
231   //      ptr = realloc(ptr, 67);
232   //      // ...
233   //    }
234   // ).
235   OAR_DoNotTrackAfterFailure
236 };
237 
238 /// Stores information about the 'fromPtr' symbol after reallocation.
239 ///
240 /// This is important because realloc may fail, and that needs special modeling.
241 /// Whether reallocation failed or not will not be known until later, so we'll
242 /// store whether upon failure 'fromPtr' will be freed, or needs to be freed
243 /// later, etc.
244 struct ReallocPair {
245 
246   // The 'fromPtr'.
247   SymbolRef ReallocatedSym;
248   OwnershipAfterReallocKind Kind;
249 
250   ReallocPair(SymbolRef S, OwnershipAfterReallocKind K)
251       : ReallocatedSym(S), Kind(K) {}
252   void Profile(llvm::FoldingSetNodeID &ID) const {
253     ID.AddInteger(Kind);
254     ID.AddPointer(ReallocatedSym);
255   }
256   bool operator==(const ReallocPair &X) const {
257     return ReallocatedSym == X.ReallocatedSym &&
258            Kind == X.Kind;
259   }
260 };
261 
262 } // end of anonymous namespace
263 
264 REGISTER_MAP_WITH_PROGRAMSTATE(ReallocPairs, SymbolRef, ReallocPair)
265 
266 //===----------------------------------------------------------------------===//
267 // Kinds of memory operations, information about resource managing functions.
268 //===----------------------------------------------------------------------===//
269 
270 namespace {
271 
272 struct MemFunctionInfoTy {
273   /// The value of the MallocChecker:Optimistic is stored in this variable.
274   ///
275   /// In pessimistic mode, the checker assumes that it does not know which
276   /// functions might free the memory.
277   /// In optimistic mode, the checker assumes that all user-defined functions
278   /// which might free a pointer are annotated.
279   DefaultBool ShouldIncludeOwnershipAnnotatedFunctions;
280 
281   CallDescription CD_alloca{{"alloca"}, 1}, CD_win_alloca{{"_alloca"}, 1},
282       CD_malloc{{"malloc"}, 1}, CD_BSD_malloc{{"malloc"}, 3},
283       CD_free{{"free"}, 1}, CD_realloc{{"realloc"}, 2},
284       CD_calloc{{"calloc"}, 2}, CD_valloc{{"valloc"}, 1},
285       CD_reallocf{{"reallocf"}, 2}, CD_strndup{{"strndup"}, 2},
286       CD_strdup{{"strdup"}, 1}, CD_win_strdup{{"_strdup"}, 1},
287       CD_kmalloc{{"kmalloc"}, 2}, CD_if_nameindex{{"if_nameindex"}, 1},
288       CD_if_freenameindex{{"if_freenameindex"}, 1}, CD_wcsdup{{"wcsdup"}, 1},
289       CD_win_wcsdup{{"_wcsdup"}, 1}, CD_kfree{{"kfree"}, 1},
290       CD_g_malloc{{"g_malloc"}, 1}, CD_g_malloc0{{"g_malloc0"}, 1},
291       CD_g_realloc{{"g_realloc"}, 2}, CD_g_try_malloc{{"g_try_malloc"}, 1},
292       CD_g_try_malloc0{{"g_try_malloc0"}, 1},
293       CD_g_try_realloc{{"g_try_realloc"}, 2}, CD_g_free{{"g_free"}, 1},
294       CD_g_memdup{{"g_memdup"}, 2}, CD_g_malloc_n{{"g_malloc_n"}, 2},
295       CD_g_malloc0_n{{"g_malloc0_n"}, 2}, CD_g_realloc_n{{"g_realloc_n"}, 3},
296       CD_g_try_malloc_n{{"g_try_malloc_n"}, 2},
297       CD_g_try_malloc0_n{{"g_try_malloc0_n"}, 2},
298       CD_g_try_realloc_n{{"g_try_realloc_n"}, 3};
299 
300   bool isMemFunction(const CallEvent &Call) const;
301   bool isCMemFunction(const CallEvent &Call) const;
302   bool isCMemFreeFunction(const CallEvent &Call) const;
303   bool isCMemAllocFunction(const CallEvent &Call) const;
304 };
305 } // end of anonymous namespace
306 
307 /// Tells if the callee is one of the builtin new/delete operators, including
308 /// placement operators and other standard overloads.
309 static bool isStandardNewDelete(const FunctionDecl *FD);
310 static bool isStandardNewDelete(const CallEvent &Call) {
311   if (!Call.getDecl())
312     return false;
313   return isStandardNewDelete(cast<FunctionDecl>(Call.getDecl()));
314 }
315 
316 //===----------------------------------------------------------------------===//
317 // Definition of the MallocChecker class.
318 //===----------------------------------------------------------------------===//
319 
320 namespace {
321 
322 class MallocChecker
323     : public Checker<check::DeadSymbols, check::PointerEscape,
324                      check::ConstPointerEscape, check::PreStmt<ReturnStmt>,
325                      check::EndFunction, check::PreCall, check::PostCall,
326                      check::PostStmt<CXXNewExpr>, check::NewAllocator,
327                      check::PreStmt<CXXDeleteExpr>, check::PostStmt<BlockExpr>,
328                      check::PostObjCMessage, check::Location, eval::Assume> {
329 public:
330   MemFunctionInfoTy MemFunctionInfo;
331 
332   /// Many checkers are essentially built into this one, so enabling them will
333   /// make MallocChecker perform additional modeling and reporting.
334   enum CheckKind {
335     /// When a subchecker is enabled but MallocChecker isn't, model memory
336     /// management but do not emit warnings emitted with MallocChecker only
337     /// enabled.
338     CK_MallocChecker,
339     CK_NewDeleteChecker,
340     CK_NewDeleteLeaksChecker,
341     CK_MismatchedDeallocatorChecker,
342     CK_InnerPointerChecker,
343     CK_NumCheckKinds
344   };
345 
346   using LeakInfo = std::pair<const ExplodedNode *, const MemRegion *>;
347 
348   DefaultBool ChecksEnabled[CK_NumCheckKinds];
349   CheckerNameRef CheckNames[CK_NumCheckKinds];
350 
351   void checkPreCall(const CallEvent &Call, CheckerContext &C) const;
352   void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
353   void checkPostStmt(const CXXNewExpr *NE, CheckerContext &C) const;
354   void checkNewAllocator(const CXXNewExpr *NE, SVal Target,
355                          CheckerContext &C) const;
356   void checkPreStmt(const CXXDeleteExpr *DE, CheckerContext &C) const;
357   void checkPostObjCMessage(const ObjCMethodCall &Call, CheckerContext &C) const;
358   void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const;
359   void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const;
360   void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const;
361   void checkEndFunction(const ReturnStmt *S, CheckerContext &C) const;
362   ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond,
363                             bool Assumption) const;
364   void checkLocation(SVal l, bool isLoad, const Stmt *S,
365                      CheckerContext &C) const;
366 
367   ProgramStateRef checkPointerEscape(ProgramStateRef State,
368                                     const InvalidatedSymbols &Escaped,
369                                     const CallEvent *Call,
370                                     PointerEscapeKind Kind) const;
371   ProgramStateRef checkConstPointerEscape(ProgramStateRef State,
372                                           const InvalidatedSymbols &Escaped,
373                                           const CallEvent *Call,
374                                           PointerEscapeKind Kind) const;
375 
376   void printState(raw_ostream &Out, ProgramStateRef State,
377                   const char *NL, const char *Sep) const override;
378 
379 private:
380   mutable std::unique_ptr<BugType> BT_DoubleFree[CK_NumCheckKinds];
381   mutable std::unique_ptr<BugType> BT_DoubleDelete;
382   mutable std::unique_ptr<BugType> BT_Leak[CK_NumCheckKinds];
383   mutable std::unique_ptr<BugType> BT_UseFree[CK_NumCheckKinds];
384   mutable std::unique_ptr<BugType> BT_BadFree[CK_NumCheckKinds];
385   mutable std::unique_ptr<BugType> BT_FreeAlloca[CK_NumCheckKinds];
386   mutable std::unique_ptr<BugType> BT_MismatchedDealloc;
387   mutable std::unique_ptr<BugType> BT_OffsetFree[CK_NumCheckKinds];
388   mutable std::unique_ptr<BugType> BT_UseZerroAllocated[CK_NumCheckKinds];
389 
390   // TODO: Remove mutable by moving the initializtaion to the registry function.
391   mutable Optional<uint64_t> KernelZeroFlagVal;
392 
393   using KernelZeroSizePtrValueTy = Optional<int>;
394   /// Store the value of macro called `ZERO_SIZE_PTR`.
395   /// The value is initialized at first use, before first use the outer
396   /// Optional is empty, afterwards it contains another Optional that indicates
397   /// if the macro value could be determined, and if yes the value itself.
398   mutable Optional<KernelZeroSizePtrValueTy> KernelZeroSizePtrValue;
399 
400   /// Process C++ operator new()'s allocation, which is the part of C++
401   /// new-expression that goes before the constructor.
402   void processNewAllocation(const CXXNewExpr *NE, CheckerContext &C,
403                             SVal Target, AllocationFamily Family) const;
404 
405   /// Perform a zero-allocation check.
406   ///
407   /// \param [in] E The expression that allocates memory.
408   /// \param [in] IndexOfSizeArg Index of the argument that specifies the size
409   ///   of the memory that needs to be allocated. E.g. for malloc, this would be
410   ///   0.
411   /// \param [in] RetVal Specifies the newly allocated pointer value;
412   ///   if unspecified, the value of expression \p E is used.
413   static ProgramStateRef ProcessZeroAllocCheck(CheckerContext &C, const Expr *E,
414                                                const unsigned IndexOfSizeArg,
415                                                ProgramStateRef State,
416                                                Optional<SVal> RetVal = None);
417 
418   /// Model functions with the ownership_returns attribute.
419   ///
420   /// User-defined function may have the ownership_returns attribute, which
421   /// annotates that the function returns with an object that was allocated on
422   /// the heap, and passes the ownertship to the callee.
423   ///
424   ///   void __attribute((ownership_returns(malloc, 1))) *my_malloc(size_t);
425   ///
426   /// It has two parameters:
427   ///   - first: name of the resource (e.g. 'malloc')
428   ///   - (OPTIONAL) second: size of the allocated region
429   ///
430   /// \param [in] CE The expression that allocates memory.
431   /// \param [in] Att The ownership_returns attribute.
432   /// \param [in] State The \c ProgramState right before allocation.
433   /// \returns The ProgramState right after allocation.
434   ProgramStateRef MallocMemReturnsAttr(CheckerContext &C,
435                                        const CallExpr *CE,
436                                        const OwnershipAttr* Att,
437                                        ProgramStateRef State) const;
438 
439   /// Models memory allocation.
440   ///
441   /// \param [in] CE The expression that allocates memory.
442   /// \param [in] SizeEx Size of the memory that needs to be allocated.
443   /// \param [in] Init The value the allocated memory needs to be initialized.
444   /// with. For example, \c calloc initializes the allocated memory to 0,
445   /// malloc leaves it undefined.
446   /// \param [in] State The \c ProgramState right before allocation.
447   /// \returns The ProgramState right after allocation.
448   static ProgramStateRef MallocMemAux(CheckerContext &C, const CallExpr *CE,
449                                       const Expr *SizeEx, SVal Init,
450                                       ProgramStateRef State,
451                                       AllocationFamily Family);
452 
453   /// Models memory allocation.
454   ///
455   /// \param [in] CE The expression that allocates memory.
456   /// \param [in] Size Size of the memory that needs to be allocated.
457   /// \param [in] Init The value the allocated memory needs to be initialized.
458   /// with. For example, \c calloc initializes the allocated memory to 0,
459   /// malloc leaves it undefined.
460   /// \param [in] State The \c ProgramState right before allocation.
461   /// \returns The ProgramState right after allocation.
462   static ProgramStateRef MallocMemAux(CheckerContext &C, const CallExpr *CE,
463                                       SVal Size, SVal Init,
464                                       ProgramStateRef State,
465                                       AllocationFamily Family);
466 
467   static ProgramStateRef addExtentSize(CheckerContext &C, const CXXNewExpr *NE,
468                                        ProgramStateRef State, SVal Target);
469 
470   // Check if this malloc() for special flags. At present that means M_ZERO or
471   // __GFP_ZERO (in which case, treat it like calloc).
472   llvm::Optional<ProgramStateRef>
473   performKernelMalloc(const CallExpr *CE, CheckerContext &C,
474                       const ProgramStateRef &State) const;
475 
476   /// Model functions with the ownership_takes and ownership_holds attributes.
477   ///
478   /// User-defined function may have the ownership_takes and/or ownership_holds
479   /// attributes, which annotates that the function frees the memory passed as a
480   /// parameter.
481   ///
482   ///   void __attribute((ownership_takes(malloc, 1))) my_free(void *);
483   ///   void __attribute((ownership_holds(malloc, 1))) my_hold(void *);
484   ///
485   /// They have two parameters:
486   ///   - first: name of the resource (e.g. 'malloc')
487   ///   - second: index of the parameter the attribute applies to
488   ///
489   /// \param [in] CE The expression that frees memory.
490   /// \param [in] Att The ownership_takes or ownership_holds attribute.
491   /// \param [in] State The \c ProgramState right before allocation.
492   /// \returns The ProgramState right after deallocation.
493   ProgramStateRef FreeMemAttr(CheckerContext &C, const CallExpr *CE,
494                               const OwnershipAttr* Att,
495                               ProgramStateRef State) const;
496 
497   /// Models memory deallocation.
498   ///
499   /// \param [in] CE The expression that frees memory.
500   /// \param [in] State The \c ProgramState right before allocation.
501   /// \param [in] Num Index of the argument that needs to be freed. This is
502   ///   normally 0, but for custom free functions it may be different.
503   /// \param [in] Hold Whether the parameter at \p Index has the ownership_holds
504   ///   attribute.
505   /// \param [out] IsKnownToBeAllocated Whether the memory to be freed is known
506   ///   to have been allocated, or in other words, the symbol to be freed was
507   ///   registered as allocated by this checker. In the following case, \c ptr
508   ///   isn't known to be allocated.
509   ///      void Haha(int *ptr) {
510   ///        ptr = realloc(ptr, 67);
511   ///        // ...
512   ///      }
513   /// \param [in] ReturnsNullOnFailure Whether the memory deallocation function
514   ///   we're modeling returns with Null on failure.
515   /// \returns The ProgramState right after deallocation.
516   ProgramStateRef FreeMemAux(CheckerContext &C, const CallExpr *CE,
517                              ProgramStateRef State, unsigned Num, bool Hold,
518                              bool &IsKnownToBeAllocated,
519                              AllocationFamily Family,
520                              bool ReturnsNullOnFailure = false) const;
521 
522   /// Models memory deallocation.
523   ///
524   /// \param [in] ArgExpr The variable who's pointee needs to be freed.
525   /// \param [in] ParentExpr The expression that frees the memory.
526   /// \param [in] State The \c ProgramState right before allocation.
527   ///   normally 0, but for custom free functions it may be different.
528   /// \param [in] Hold Whether the parameter at \p Index has the ownership_holds
529   ///   attribute.
530   /// \param [out] IsKnownToBeAllocated Whether the memory to be freed is known
531   ///   to have been allocated, or in other words, the symbol to be freed was
532   ///   registered as allocated by this checker. In the following case, \c ptr
533   ///   isn't known to be allocated.
534   ///      void Haha(int *ptr) {
535   ///        ptr = realloc(ptr, 67);
536   ///        // ...
537   ///      }
538   /// \param [in] ReturnsNullOnFailure Whether the memory deallocation function
539   ///   we're modeling returns with Null on failure.
540   /// \returns The ProgramState right after deallocation.
541   ProgramStateRef FreeMemAux(CheckerContext &C, const Expr *ArgExpr,
542                              const Expr *ParentExpr, ProgramStateRef State,
543                              bool Hold, bool &IsKnownToBeAllocated,
544                              AllocationFamily Family,
545                              bool ReturnsNullOnFailure = false) const;
546 
547   // TODO: Needs some refactoring, as all other deallocation modeling
548   // functions are suffering from out parameters and messy code due to how
549   // realloc is handled.
550   //
551   /// Models memory reallocation.
552   ///
553   /// \param [in] CE The expression that reallocated memory
554   /// \param [in] ShouldFreeOnFail Whether if reallocation fails, the supplied
555   ///   memory should be freed.
556   /// \param [in] State The \c ProgramState right before reallocation.
557   /// \param [in] SuffixWithN Whether the reallocation function we're modeling
558   ///   has an '_n' suffix, such as g_realloc_n.
559   /// \returns The ProgramState right after reallocation.
560   ProgramStateRef ReallocMemAux(CheckerContext &C, const CallExpr *CE,
561                                 bool ShouldFreeOnFail, ProgramStateRef State,
562                                 AllocationFamily Family,
563                                 bool SuffixWithN = false) const;
564 
565   /// Evaluates the buffer size that needs to be allocated.
566   ///
567   /// \param [in] Blocks The amount of blocks that needs to be allocated.
568   /// \param [in] BlockBytes The size of a block.
569   /// \returns The symbolic value of \p Blocks * \p BlockBytes.
570   static SVal evalMulForBufferSize(CheckerContext &C, const Expr *Blocks,
571                                    const Expr *BlockBytes);
572 
573   /// Models zero initialized array allocation.
574   ///
575   /// \param [in] CE The expression that reallocated memory
576   /// \param [in] State The \c ProgramState right before reallocation.
577   /// \returns The ProgramState right after allocation.
578   static ProgramStateRef CallocMem(CheckerContext &C, const CallExpr *CE,
579                                    ProgramStateRef State);
580 
581   /// See if deallocation happens in a suspicious context. If so, escape the
582   /// pointers that otherwise would have been deallocated and return true.
583   bool suppressDeallocationsInSuspiciousContexts(const CallExpr *CE,
584                                                  CheckerContext &C) const;
585 
586   /// If in \p S  \p Sym is used, check whether \p Sym was already freed.
587   bool checkUseAfterFree(SymbolRef Sym, CheckerContext &C, const Stmt *S) const;
588 
589   /// If in \p S \p Sym is used, check whether \p Sym was allocated as a zero
590   /// sized memory region.
591   void checkUseZeroAllocated(SymbolRef Sym, CheckerContext &C,
592                              const Stmt *S) const;
593 
594   /// If in \p S \p Sym is being freed, check whether \p Sym was already freed.
595   bool checkDoubleDelete(SymbolRef Sym, CheckerContext &C) const;
596 
597   /// Check if the function is known to free memory, or if it is
598   /// "interesting" and should be modeled explicitly.
599   ///
600   /// \param [out] EscapingSymbol A function might not free memory in general,
601   ///   but could be known to free a particular symbol. In this case, false is
602   ///   returned and the single escaping symbol is returned through the out
603   ///   parameter.
604   ///
605   /// We assume that pointers do not escape through calls to system functions
606   /// not handled by this checker.
607   bool mayFreeAnyEscapedMemoryOrIsModeledExplicitly(const CallEvent *Call,
608                                    ProgramStateRef State,
609                                    SymbolRef &EscapingSymbol) const;
610 
611   /// Implementation of the checkPointerEscape callbacks.
612   ProgramStateRef checkPointerEscapeAux(ProgramStateRef State,
613                                         const InvalidatedSymbols &Escaped,
614                                         const CallEvent *Call,
615                                         PointerEscapeKind Kind,
616                                         bool IsConstPointerEscape) const;
617 
618   // Implementation of the checkPreStmt and checkEndFunction callbacks.
619   void checkEscapeOnReturn(const ReturnStmt *S, CheckerContext &C) const;
620 
621   ///@{
622   /// Tells if a given family/call/symbol is tracked by the current checker.
623   /// Sets CheckKind to the kind of the checker responsible for this
624   /// family/call/symbol.
625   Optional<CheckKind> getCheckIfTracked(AllocationFamily Family,
626                                         bool IsALeakCheck = false) const;
627 
628   Optional<CheckKind> getCheckIfTracked(CheckerContext &C, SymbolRef Sym,
629                                         bool IsALeakCheck = false) const;
630   ///@}
631   static bool SummarizeValue(raw_ostream &os, SVal V);
632   static bool SummarizeRegion(raw_ostream &os, const MemRegion *MR);
633 
634   void ReportBadFree(CheckerContext &C, SVal ArgVal, SourceRange Range,
635                      const Expr *DeallocExpr, AllocationFamily Family) const;
636 
637   void ReportFreeAlloca(CheckerContext &C, SVal ArgVal,
638                         SourceRange Range) const;
639 
640   void ReportMismatchedDealloc(CheckerContext &C, SourceRange Range,
641                                const Expr *DeallocExpr, const RefState *RS,
642                                SymbolRef Sym, bool OwnershipTransferred) const;
643 
644   void ReportOffsetFree(CheckerContext &C, SVal ArgVal, SourceRange Range,
645                         const Expr *DeallocExpr, AllocationFamily Family,
646                         const Expr *AllocExpr = nullptr) const;
647 
648   void ReportUseAfterFree(CheckerContext &C, SourceRange Range,
649                           SymbolRef Sym) const;
650 
651   void ReportDoubleFree(CheckerContext &C, SourceRange Range, bool Released,
652                         SymbolRef Sym, SymbolRef PrevSym) const;
653 
654   void ReportDoubleDelete(CheckerContext &C, SymbolRef Sym) const;
655 
656   void ReportUseZeroAllocated(CheckerContext &C, SourceRange Range,
657                               SymbolRef Sym) const;
658 
659   void ReportFunctionPointerFree(CheckerContext &C, SVal ArgVal,
660                                  SourceRange Range, const Expr *FreeExpr,
661                                  AllocationFamily Family) const;
662 
663   /// Find the location of the allocation for Sym on the path leading to the
664   /// exploded node N.
665   static LeakInfo getAllocationSite(const ExplodedNode *N, SymbolRef Sym,
666                                     CheckerContext &C);
667 
668   void reportLeak(SymbolRef Sym, ExplodedNode *N, CheckerContext &C) const;
669 
670   /// Test if value in ArgVal equals to value in macro `ZERO_SIZE_PTR`.
671   bool isArgZERO_SIZE_PTR(ProgramStateRef State, CheckerContext &C,
672                           SVal ArgVal) const;
673 };
674 
675 //===----------------------------------------------------------------------===//
676 // Definition of MallocBugVisitor.
677 //===----------------------------------------------------------------------===//
678 
679 /// The bug visitor which allows us to print extra diagnostics along the
680 /// BugReport path. For example, showing the allocation site of the leaked
681 /// region.
682 class MallocBugVisitor final : public BugReporterVisitor {
683 protected:
684   enum NotificationMode { Normal, ReallocationFailed };
685 
686   // The allocated region symbol tracked by the main analysis.
687   SymbolRef Sym;
688 
689   // The mode we are in, i.e. what kind of diagnostics will be emitted.
690   NotificationMode Mode;
691 
692   // A symbol from when the primary region should have been reallocated.
693   SymbolRef FailedReallocSymbol;
694 
695   // A C++ destructor stack frame in which memory was released. Used for
696   // miscellaneous false positive suppression.
697   const StackFrameContext *ReleaseDestructorLC;
698 
699   bool IsLeak;
700 
701 public:
702   MallocBugVisitor(SymbolRef S, bool isLeak = false)
703       : Sym(S), Mode(Normal), FailedReallocSymbol(nullptr),
704         ReleaseDestructorLC(nullptr), IsLeak(isLeak) {}
705 
706   static void *getTag() {
707     static int Tag = 0;
708     return &Tag;
709   }
710 
711   void Profile(llvm::FoldingSetNodeID &ID) const override {
712     ID.AddPointer(getTag());
713     ID.AddPointer(Sym);
714   }
715 
716   /// Did not track -> allocated. Other state (released) -> allocated.
717   static inline bool isAllocated(const RefState *RSCurr, const RefState *RSPrev,
718                                  const Stmt *Stmt) {
719     return (Stmt && (isa<CallExpr>(Stmt) || isa<CXXNewExpr>(Stmt)) &&
720             (RSCurr &&
721              (RSCurr->isAllocated() || RSCurr->isAllocatedOfSizeZero())) &&
722             (!RSPrev ||
723              !(RSPrev->isAllocated() || RSPrev->isAllocatedOfSizeZero())));
724   }
725 
726   /// Did not track -> released. Other state (allocated) -> released.
727   /// The statement associated with the release might be missing.
728   static inline bool isReleased(const RefState *RSCurr, const RefState *RSPrev,
729                                 const Stmt *Stmt) {
730     bool IsReleased =
731         (RSCurr && RSCurr->isReleased()) && (!RSPrev || !RSPrev->isReleased());
732     assert(!IsReleased ||
733            (Stmt && (isa<CallExpr>(Stmt) || isa<CXXDeleteExpr>(Stmt))) ||
734            (!Stmt && RSCurr->getAllocationFamily() == AF_InnerBuffer));
735     return IsReleased;
736   }
737 
738   /// Did not track -> relinquished. Other state (allocated) -> relinquished.
739   static inline bool isRelinquished(const RefState *RSCurr,
740                                     const RefState *RSPrev, const Stmt *Stmt) {
741     return (Stmt &&
742             (isa<CallExpr>(Stmt) || isa<ObjCMessageExpr>(Stmt) ||
743              isa<ObjCPropertyRefExpr>(Stmt)) &&
744             (RSCurr && RSCurr->isRelinquished()) &&
745             (!RSPrev || !RSPrev->isRelinquished()));
746   }
747 
748   /// If the expression is not a call, and the state change is
749   /// released -> allocated, it must be the realloc return value
750   /// check. If we have to handle more cases here, it might be cleaner just
751   /// to track this extra bit in the state itself.
752   static inline bool hasReallocFailed(const RefState *RSCurr,
753                                       const RefState *RSPrev,
754                                       const Stmt *Stmt) {
755     return ((!Stmt || !isa<CallExpr>(Stmt)) &&
756             (RSCurr &&
757              (RSCurr->isAllocated() || RSCurr->isAllocatedOfSizeZero())) &&
758             (RSPrev &&
759              !(RSPrev->isAllocated() || RSPrev->isAllocatedOfSizeZero())));
760   }
761 
762   PathDiagnosticPieceRef VisitNode(const ExplodedNode *N,
763                                    BugReporterContext &BRC,
764                                    PathSensitiveBugReport &BR) override;
765 
766   PathDiagnosticPieceRef getEndPath(BugReporterContext &BRC,
767                                     const ExplodedNode *EndPathNode,
768                                     PathSensitiveBugReport &BR) override {
769     if (!IsLeak)
770       return nullptr;
771 
772     PathDiagnosticLocation L = BR.getLocation();
773     // Do not add the statement itself as a range in case of leak.
774     return std::make_shared<PathDiagnosticEventPiece>(L, BR.getDescription(),
775                                                       false);
776   }
777 
778 private:
779   class StackHintGeneratorForReallocationFailed
780       : public StackHintGeneratorForSymbol {
781   public:
782     StackHintGeneratorForReallocationFailed(SymbolRef S, StringRef M)
783         : StackHintGeneratorForSymbol(S, M) {}
784 
785     std::string getMessageForArg(const Expr *ArgE, unsigned ArgIndex) override {
786       // Printed parameters start at 1, not 0.
787       ++ArgIndex;
788 
789       SmallString<200> buf;
790       llvm::raw_svector_ostream os(buf);
791 
792       os << "Reallocation of " << ArgIndex << llvm::getOrdinalSuffix(ArgIndex)
793          << " parameter failed";
794 
795       return std::string(os.str());
796     }
797 
798     std::string getMessageForReturn(const CallExpr *CallExpr) override {
799       return "Reallocation of returned value failed";
800     }
801   };
802 };
803 
804 } // end anonymous namespace
805 
806 // A map from the freed symbol to the symbol representing the return value of
807 // the free function.
808 REGISTER_MAP_WITH_PROGRAMSTATE(FreeReturnValue, SymbolRef, SymbolRef)
809 
810 namespace {
811 class StopTrackingCallback final : public SymbolVisitor {
812   ProgramStateRef state;
813 
814 public:
815   StopTrackingCallback(ProgramStateRef st) : state(std::move(st)) {}
816   ProgramStateRef getState() const { return state; }
817 
818   bool VisitSymbol(SymbolRef sym) override {
819     state = state->remove<RegionState>(sym);
820     return true;
821   }
822 };
823 } // end anonymous namespace
824 
825 //===----------------------------------------------------------------------===//
826 // Methods of MemFunctionInfoTy.
827 //===----------------------------------------------------------------------===//
828 
829 bool MemFunctionInfoTy::isMemFunction(const CallEvent &Call) const {
830   return isCMemFunction(Call) || isStandardNewDelete(Call);
831 }
832 
833 bool MemFunctionInfoTy::isCMemFunction(const CallEvent &Call) const {
834   return isCMemFreeFunction(Call) || isCMemAllocFunction(Call);
835 }
836 
837 bool MemFunctionInfoTy::isCMemFreeFunction(const CallEvent &Call) const {
838   if (Call.isCalled(CD_free, CD_realloc, CD_reallocf, CD_g_free, CD_kfree))
839     return true;
840 
841   if (Call.isCalled(CD_if_freenameindex))
842     return true;
843 
844   if (!ShouldIncludeOwnershipAnnotatedFunctions)
845     return false;
846 
847   const auto *Func = dyn_cast<FunctionDecl>(Call.getDecl());
848   if (Func && Func->hasAttrs()) {
849     for (const auto *I : Func->specific_attrs<OwnershipAttr>()) {
850       OwnershipAttr::OwnershipKind OwnKind = I->getOwnKind();
851       if (OwnKind == OwnershipAttr::Takes || OwnKind == OwnershipAttr::Holds)
852         return true;
853     }
854   }
855   return false;
856 }
857 
858 bool MemFunctionInfoTy::isCMemAllocFunction(const CallEvent &Call) const {
859   if (Call.isCalled(CD_malloc, CD_realloc, CD_reallocf, CD_calloc, CD_valloc,
860                     CD_strdup, CD_win_strdup, CD_strndup, CD_wcsdup,
861                     CD_win_wcsdup, CD_kmalloc, CD_g_malloc, CD_g_malloc0,
862                     CD_g_realloc, CD_g_try_malloc, CD_g_try_malloc0,
863                     CD_g_try_realloc, CD_g_memdup, CD_g_malloc_n,
864                     CD_g_malloc0_n, CD_g_realloc_n, CD_g_try_malloc_n,
865                     CD_g_try_malloc0_n, CD_g_try_realloc_n))
866     return true;
867 
868   if (Call.isCalled(CD_if_nameindex))
869     return true;
870 
871   if (Call.isCalled(CD_alloca, CD_win_alloca))
872     return true;
873 
874   if (!ShouldIncludeOwnershipAnnotatedFunctions)
875     return false;
876 
877   const auto *Func = dyn_cast<FunctionDecl>(Call.getDecl());
878   if (Func && Func->hasAttrs()) {
879     for (const auto *I : Func->specific_attrs<OwnershipAttr>()) {
880       OwnershipAttr::OwnershipKind OwnKind = I->getOwnKind();
881       if (OwnKind == OwnershipAttr::Returns)
882         return true;
883     }
884   }
885 
886   return false;
887 }
888 
889 static bool isStandardNewDelete(const FunctionDecl *FD) {
890   if (!FD)
891     return false;
892 
893   OverloadedOperatorKind Kind = FD->getOverloadedOperator();
894   if (Kind != OO_New && Kind != OO_Array_New && Kind != OO_Delete &&
895       Kind != OO_Array_Delete)
896     return false;
897 
898   // This is standard if and only if it's not defined in a user file.
899   SourceLocation L = FD->getLocation();
900   // If the header for operator delete is not included, it's still defined
901   // in an invalid source location. Check to make sure we don't crash.
902   return !L.isValid() ||
903          FD->getASTContext().getSourceManager().isInSystemHeader(L);
904 }
905 
906 //===----------------------------------------------------------------------===//
907 // Methods of MallocChecker and MallocBugVisitor.
908 //===----------------------------------------------------------------------===//
909 
910 llvm::Optional<ProgramStateRef> MallocChecker::performKernelMalloc(
911   const CallExpr *CE, CheckerContext &C, const ProgramStateRef &State) const {
912   // 3-argument malloc(), as commonly used in {Free,Net,Open}BSD Kernels:
913   //
914   // void *malloc(unsigned long size, struct malloc_type *mtp, int flags);
915   //
916   // One of the possible flags is M_ZERO, which means 'give me back an
917   // allocation which is already zeroed', like calloc.
918 
919   // 2-argument kmalloc(), as used in the Linux kernel:
920   //
921   // void *kmalloc(size_t size, gfp_t flags);
922   //
923   // Has the similar flag value __GFP_ZERO.
924 
925   // This logic is largely cloned from O_CREAT in UnixAPIChecker, maybe some
926   // code could be shared.
927 
928   ASTContext &Ctx = C.getASTContext();
929   llvm::Triple::OSType OS = Ctx.getTargetInfo().getTriple().getOS();
930 
931   if (!KernelZeroFlagVal.hasValue()) {
932     if (OS == llvm::Triple::FreeBSD)
933       KernelZeroFlagVal = 0x0100;
934     else if (OS == llvm::Triple::NetBSD)
935       KernelZeroFlagVal = 0x0002;
936     else if (OS == llvm::Triple::OpenBSD)
937       KernelZeroFlagVal = 0x0008;
938     else if (OS == llvm::Triple::Linux)
939       // __GFP_ZERO
940       KernelZeroFlagVal = 0x8000;
941     else
942       // FIXME: We need a more general way of getting the M_ZERO value.
943       // See also: O_CREAT in UnixAPIChecker.cpp.
944 
945       // Fall back to normal malloc behavior on platforms where we don't
946       // know M_ZERO.
947       return None;
948   }
949 
950   // We treat the last argument as the flags argument, and callers fall-back to
951   // normal malloc on a None return. This works for the FreeBSD kernel malloc
952   // as well as Linux kmalloc.
953   if (CE->getNumArgs() < 2)
954     return None;
955 
956   const Expr *FlagsEx = CE->getArg(CE->getNumArgs() - 1);
957   const SVal V = C.getSVal(FlagsEx);
958   if (!V.getAs<NonLoc>()) {
959     // The case where 'V' can be a location can only be due to a bad header,
960     // so in this case bail out.
961     return None;
962   }
963 
964   NonLoc Flags = V.castAs<NonLoc>();
965   NonLoc ZeroFlag = C.getSValBuilder()
966       .makeIntVal(KernelZeroFlagVal.getValue(), FlagsEx->getType())
967       .castAs<NonLoc>();
968   SVal MaskedFlagsUC = C.getSValBuilder().evalBinOpNN(State, BO_And,
969                                                       Flags, ZeroFlag,
970                                                       FlagsEx->getType());
971   if (MaskedFlagsUC.isUnknownOrUndef())
972     return None;
973   DefinedSVal MaskedFlags = MaskedFlagsUC.castAs<DefinedSVal>();
974 
975   // Check if maskedFlags is non-zero.
976   ProgramStateRef TrueState, FalseState;
977   std::tie(TrueState, FalseState) = State->assume(MaskedFlags);
978 
979   // If M_ZERO is set, treat this like calloc (initialized).
980   if (TrueState && !FalseState) {
981     SVal ZeroVal = C.getSValBuilder().makeZeroVal(Ctx.CharTy);
982     return MallocMemAux(C, CE, CE->getArg(0), ZeroVal, TrueState, AF_Malloc);
983   }
984 
985   return None;
986 }
987 
988 SVal MallocChecker::evalMulForBufferSize(CheckerContext &C, const Expr *Blocks,
989                                          const Expr *BlockBytes) {
990   SValBuilder &SB = C.getSValBuilder();
991   SVal BlocksVal = C.getSVal(Blocks);
992   SVal BlockBytesVal = C.getSVal(BlockBytes);
993   ProgramStateRef State = C.getState();
994   SVal TotalSize = SB.evalBinOp(State, BO_Mul, BlocksVal, BlockBytesVal,
995                                 SB.getContext().getSizeType());
996   return TotalSize;
997 }
998 
999 void MallocChecker::checkPostCall(const CallEvent &Call,
1000                                   CheckerContext &C) const {
1001   if (C.wasInlined)
1002     return;
1003 
1004   const auto *CE = dyn_cast_or_null<CallExpr>(Call.getOriginExpr());
1005   if (!CE)
1006     return;
1007 
1008   const FunctionDecl *FD = C.getCalleeDecl(CE);
1009   if (!FD)
1010     return;
1011 
1012   ProgramStateRef State = C.getState();
1013   bool IsKnownToBeAllocatedMemory = false;
1014 
1015   if (FD->getKind() == Decl::Function) {
1016     if (Call.isCalled(MemFunctionInfo.CD_malloc, MemFunctionInfo.CD_BSD_malloc,
1017                       MemFunctionInfo.CD_g_malloc,
1018                       MemFunctionInfo.CD_g_try_malloc)) {
1019       switch (CE->getNumArgs()) {
1020       default:
1021         return;
1022       case 1:
1023         State = MallocMemAux(C, CE, CE->getArg(0), UndefinedVal(), State,
1024                              AF_Malloc);
1025         State = ProcessZeroAllocCheck(C, CE, 0, State);
1026         break;
1027       case 2:
1028         llvm_unreachable("There shouldn't be a 2-argument malloc!");
1029         break;
1030       case 3:
1031         llvm::Optional<ProgramStateRef> MaybeState =
1032           performKernelMalloc(CE, C, State);
1033         if (MaybeState.hasValue())
1034           State = MaybeState.getValue();
1035         else
1036           State = MallocMemAux(C, CE, CE->getArg(0), UndefinedVal(), State,
1037                                AF_Malloc);
1038         break;
1039       }
1040     } else if (Call.isCalled(MemFunctionInfo.CD_kmalloc)) {
1041       if (CE->getNumArgs() < 1)
1042         return;
1043       llvm::Optional<ProgramStateRef> MaybeState =
1044           performKernelMalloc(CE, C, State);
1045       if (MaybeState.hasValue())
1046         State = MaybeState.getValue();
1047       else
1048         State = MallocMemAux(C, CE, CE->getArg(0), UndefinedVal(), State,
1049                              AF_Malloc);
1050     } else if (Call.isCalled(MemFunctionInfo.CD_valloc)) {
1051       if (CE->getNumArgs() < 1)
1052         return;
1053       State =
1054           MallocMemAux(C, CE, CE->getArg(0), UndefinedVal(), State, AF_Malloc);
1055       State = ProcessZeroAllocCheck(C, CE, 0, State);
1056     } else if (Call.isCalled(MemFunctionInfo.CD_realloc,
1057                              MemFunctionInfo.CD_g_realloc,
1058                              MemFunctionInfo.CD_g_try_realloc)) {
1059       State =
1060           ReallocMemAux(C, CE, /*ShouldFreeOnFail*/ false, State, AF_Malloc);
1061       State = ProcessZeroAllocCheck(C, CE, 1, State);
1062     } else if (Call.isCalled(MemFunctionInfo.CD_reallocf)) {
1063       State = ReallocMemAux(C, CE, /*ShouldFreeOnFail*/ true, State, AF_Malloc);
1064       State = ProcessZeroAllocCheck(C, CE, 1, State);
1065     } else if (Call.isCalled(MemFunctionInfo.CD_calloc)) {
1066       State = CallocMem(C, CE, State);
1067       State = ProcessZeroAllocCheck(C, CE, 0, State);
1068       State = ProcessZeroAllocCheck(C, CE, 1, State);
1069     } else if (Call.isCalled(MemFunctionInfo.CD_free, MemFunctionInfo.CD_g_free,
1070                              MemFunctionInfo.CD_kfree)) {
1071       if (suppressDeallocationsInSuspiciousContexts(CE, C))
1072         return;
1073 
1074       State = FreeMemAux(C, CE, State, 0, false, IsKnownToBeAllocatedMemory,
1075                          AF_Malloc);
1076     } else if (Call.isCalled(
1077                    MemFunctionInfo.CD_strdup, MemFunctionInfo.CD_win_strdup,
1078                    MemFunctionInfo.CD_wcsdup, MemFunctionInfo.CD_win_wcsdup)) {
1079       State = MallocUpdateRefState(C, CE, State, AF_Malloc);
1080     } else if (Call.isCalled(MemFunctionInfo.CD_strndup)) {
1081       State = MallocUpdateRefState(C, CE, State, AF_Malloc);
1082     } else if (Call.isCalled(MemFunctionInfo.CD_alloca,
1083                              MemFunctionInfo.CD_win_alloca)) {
1084       if (CE->getNumArgs() < 1)
1085         return;
1086       State =
1087           MallocMemAux(C, CE, CE->getArg(0), UndefinedVal(), State, AF_Alloca);
1088       State = ProcessZeroAllocCheck(C, CE, 0, State);
1089     } else if (isStandardNewDelete(FD)) {
1090       // Process direct calls to operator new/new[]/delete/delete[] functions
1091       // as distinct from new/new[]/delete/delete[] expressions that are
1092       // processed by the checkPostStmt callbacks for CXXNewExpr and
1093       // CXXDeleteExpr.
1094       switch (FD->getOverloadedOperator()) {
1095       case OO_New:
1096         State = MallocMemAux(C, CE, CE->getArg(0), UndefinedVal(), State,
1097                              AF_CXXNew);
1098         State = ProcessZeroAllocCheck(C, CE, 0, State);
1099         break;
1100       case OO_Array_New:
1101         State = MallocMemAux(C, CE, CE->getArg(0), UndefinedVal(), State,
1102                              AF_CXXNewArray);
1103         State = ProcessZeroAllocCheck(C, CE, 0, State);
1104         break;
1105       case OO_Delete:
1106         State = FreeMemAux(C, CE, State, 0, false, IsKnownToBeAllocatedMemory,
1107                            AF_CXXNew);
1108         break;
1109       case OO_Array_Delete:
1110         State = FreeMemAux(C, CE, State, 0, false, IsKnownToBeAllocatedMemory,
1111                            AF_CXXNewArray);
1112         break;
1113       default:
1114         llvm_unreachable("not a new/delete operator");
1115       }
1116     } else if (Call.isCalled(MemFunctionInfo.CD_if_nameindex)) {
1117       // Should we model this differently? We can allocate a fixed number of
1118       // elements with zeros in the last one.
1119       State = MallocMemAux(C, CE, UnknownVal(), UnknownVal(), State,
1120                            AF_IfNameIndex);
1121     } else if (Call.isCalled(MemFunctionInfo.CD_if_freenameindex)) {
1122       State = FreeMemAux(C, CE, State, 0, false, IsKnownToBeAllocatedMemory,
1123                          AF_IfNameIndex);
1124     } else if (Call.isCalled(MemFunctionInfo.CD_g_malloc0,
1125                              MemFunctionInfo.CD_g_try_malloc0)) {
1126       if (CE->getNumArgs() < 1)
1127         return;
1128       SValBuilder &svalBuilder = C.getSValBuilder();
1129       SVal zeroVal = svalBuilder.makeZeroVal(svalBuilder.getContext().CharTy);
1130       State = MallocMemAux(C, CE, CE->getArg(0), zeroVal, State, AF_Malloc);
1131       State = ProcessZeroAllocCheck(C, CE, 0, State);
1132     } else if (Call.isCalled(MemFunctionInfo.CD_g_memdup)) {
1133       if (CE->getNumArgs() < 2)
1134         return;
1135       State =
1136           MallocMemAux(C, CE, CE->getArg(1), UndefinedVal(), State, AF_Malloc);
1137       State = ProcessZeroAllocCheck(C, CE, 1, State);
1138     } else if (Call.isCalled(MemFunctionInfo.CD_g_malloc_n,
1139                              MemFunctionInfo.CD_g_try_malloc_n,
1140                              MemFunctionInfo.CD_g_malloc0_n,
1141                              MemFunctionInfo.CD_g_try_malloc0_n)) {
1142       if (CE->getNumArgs() < 2)
1143         return;
1144       SVal Init = UndefinedVal();
1145       if (Call.isCalled(MemFunctionInfo.CD_g_malloc0_n,
1146                         MemFunctionInfo.CD_g_try_malloc0_n)) {
1147         SValBuilder &SB = C.getSValBuilder();
1148         Init = SB.makeZeroVal(SB.getContext().CharTy);
1149       }
1150       SVal TotalSize = evalMulForBufferSize(C, CE->getArg(0), CE->getArg(1));
1151       State = MallocMemAux(C, CE, TotalSize, Init, State, AF_Malloc);
1152       State = ProcessZeroAllocCheck(C, CE, 0, State);
1153       State = ProcessZeroAllocCheck(C, CE, 1, State);
1154     } else if (Call.isCalled(MemFunctionInfo.CD_g_realloc_n,
1155                              MemFunctionInfo.CD_g_try_realloc_n)) {
1156       if (CE->getNumArgs() < 3)
1157         return;
1158       State = ReallocMemAux(C, CE, /*ShouldFreeOnFail*/ false, State, AF_Malloc,
1159                             /*SuffixWithN*/ true);
1160       State = ProcessZeroAllocCheck(C, CE, 1, State);
1161       State = ProcessZeroAllocCheck(C, CE, 2, State);
1162     }
1163   }
1164 
1165   if (MemFunctionInfo.ShouldIncludeOwnershipAnnotatedFunctions ||
1166       ChecksEnabled[CK_MismatchedDeallocatorChecker]) {
1167     // Check all the attributes, if there are any.
1168     // There can be multiple of these attributes.
1169     if (FD->hasAttrs())
1170       for (const auto *I : FD->specific_attrs<OwnershipAttr>()) {
1171         switch (I->getOwnKind()) {
1172         case OwnershipAttr::Returns:
1173           State = MallocMemReturnsAttr(C, CE, I, State);
1174           break;
1175         case OwnershipAttr::Takes:
1176         case OwnershipAttr::Holds:
1177           State = FreeMemAttr(C, CE, I, State);
1178           break;
1179         }
1180       }
1181   }
1182   C.addTransition(State);
1183 }
1184 
1185 // Performs a 0-sized allocations check.
1186 ProgramStateRef MallocChecker::ProcessZeroAllocCheck(
1187     CheckerContext &C, const Expr *E, const unsigned IndexOfSizeArg,
1188     ProgramStateRef State, Optional<SVal> RetVal) {
1189   if (!State)
1190     return nullptr;
1191 
1192   if (!RetVal)
1193     RetVal = C.getSVal(E);
1194 
1195   const Expr *Arg = nullptr;
1196 
1197   if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
1198     Arg = CE->getArg(IndexOfSizeArg);
1199   }
1200   else if (const CXXNewExpr *NE = dyn_cast<CXXNewExpr>(E)) {
1201     if (NE->isArray())
1202       Arg = *NE->getArraySize();
1203     else
1204       return State;
1205   }
1206   else
1207     llvm_unreachable("not a CallExpr or CXXNewExpr");
1208 
1209   assert(Arg);
1210 
1211   Optional<DefinedSVal> DefArgVal = C.getSVal(Arg).getAs<DefinedSVal>();
1212 
1213   if (!DefArgVal)
1214     return State;
1215 
1216   // Check if the allocation size is 0.
1217   ProgramStateRef TrueState, FalseState;
1218   SValBuilder &SvalBuilder = C.getSValBuilder();
1219   DefinedSVal Zero =
1220       SvalBuilder.makeZeroVal(Arg->getType()).castAs<DefinedSVal>();
1221 
1222   std::tie(TrueState, FalseState) =
1223       State->assume(SvalBuilder.evalEQ(State, *DefArgVal, Zero));
1224 
1225   if (TrueState && !FalseState) {
1226     SymbolRef Sym = RetVal->getAsLocSymbol();
1227     if (!Sym)
1228       return State;
1229 
1230     const RefState *RS = State->get<RegionState>(Sym);
1231     if (RS) {
1232       if (RS->isAllocated())
1233         return TrueState->set<RegionState>(Sym,
1234                                           RefState::getAllocatedOfSizeZero(RS));
1235       else
1236         return State;
1237     } else {
1238       // Case of zero-size realloc. Historically 'realloc(ptr, 0)' is treated as
1239       // 'free(ptr)' and the returned value from 'realloc(ptr, 0)' is not
1240       // tracked. Add zero-reallocated Sym to the state to catch references
1241       // to zero-allocated memory.
1242       return TrueState->add<ReallocSizeZeroSymbols>(Sym);
1243     }
1244   }
1245 
1246   // Assume the value is non-zero going forward.
1247   assert(FalseState);
1248   return FalseState;
1249 }
1250 
1251 static QualType getDeepPointeeType(QualType T) {
1252   QualType Result = T, PointeeType = T->getPointeeType();
1253   while (!PointeeType.isNull()) {
1254     Result = PointeeType;
1255     PointeeType = PointeeType->getPointeeType();
1256   }
1257   return Result;
1258 }
1259 
1260 /// \returns true if the constructor invoked by \p NE has an argument of a
1261 /// pointer/reference to a record type.
1262 static bool hasNonTrivialConstructorCall(const CXXNewExpr *NE) {
1263 
1264   const CXXConstructExpr *ConstructE = NE->getConstructExpr();
1265   if (!ConstructE)
1266     return false;
1267 
1268   if (!NE->getAllocatedType()->getAsCXXRecordDecl())
1269     return false;
1270 
1271   const CXXConstructorDecl *CtorD = ConstructE->getConstructor();
1272 
1273   // Iterate over the constructor parameters.
1274   for (const auto *CtorParam : CtorD->parameters()) {
1275 
1276     QualType CtorParamPointeeT = CtorParam->getType()->getPointeeType();
1277     if (CtorParamPointeeT.isNull())
1278       continue;
1279 
1280     CtorParamPointeeT = getDeepPointeeType(CtorParamPointeeT);
1281 
1282     if (CtorParamPointeeT->getAsCXXRecordDecl())
1283       return true;
1284   }
1285 
1286   return false;
1287 }
1288 
1289 void MallocChecker::processNewAllocation(const CXXNewExpr *NE,
1290                                          CheckerContext &C, SVal Target,
1291                                          AllocationFamily Family) const {
1292   if (!isStandardNewDelete(NE->getOperatorNew()))
1293     return;
1294 
1295   const ParentMap &PM = C.getLocationContext()->getParentMap();
1296 
1297   // Non-trivial constructors have a chance to escape 'this', but marking all
1298   // invocations of trivial constructors as escaped would cause too great of
1299   // reduction of true positives, so let's just do that for constructors that
1300   // have an argument of a pointer-to-record type.
1301   if (!PM.isConsumedExpr(NE) && hasNonTrivialConstructorCall(NE))
1302     return;
1303 
1304   ProgramStateRef State = C.getState();
1305   // The return value from operator new is bound to a specified initialization
1306   // value (if any) and we don't want to loose this value. So we call
1307   // MallocUpdateRefState() instead of MallocMemAux() which breaks the
1308   // existing binding.
1309   State = MallocUpdateRefState(C, NE, State, Family, Target);
1310   State = addExtentSize(C, NE, State, Target);
1311   State = ProcessZeroAllocCheck(C, NE, 0, State, Target);
1312   C.addTransition(State);
1313 }
1314 
1315 void MallocChecker::checkPostStmt(const CXXNewExpr *NE,
1316                                   CheckerContext &C) const {
1317   if (!C.getAnalysisManager().getAnalyzerOptions().MayInlineCXXAllocator) {
1318     if (NE->isArray())
1319       processNewAllocation(NE, C, C.getSVal(NE),
1320                            (NE->isArray() ? AF_CXXNewArray : AF_CXXNew));
1321   }
1322 }
1323 
1324 void MallocChecker::checkNewAllocator(const CXXNewExpr *NE, SVal Target,
1325                                       CheckerContext &C) const {
1326   if (!C.wasInlined) {
1327     processNewAllocation(NE, C, Target,
1328                          (NE->isArray() ? AF_CXXNewArray : AF_CXXNew));
1329   }
1330 }
1331 
1332 // Sets the extent value of the MemRegion allocated by
1333 // new expression NE to its size in Bytes.
1334 //
1335 ProgramStateRef MallocChecker::addExtentSize(CheckerContext &C,
1336                                              const CXXNewExpr *NE,
1337                                              ProgramStateRef State,
1338                                              SVal Target) {
1339   if (!State)
1340     return nullptr;
1341   SValBuilder &svalBuilder = C.getSValBuilder();
1342   SVal ElementCount;
1343   const SubRegion *Region;
1344   if (NE->isArray()) {
1345     const Expr *SizeExpr = *NE->getArraySize();
1346     ElementCount = C.getSVal(SizeExpr);
1347     // Store the extent size for the (symbolic)region
1348     // containing the elements.
1349     Region = Target.getAsRegion()
1350                  ->castAs<SubRegion>()
1351                  ->StripCasts()
1352                  ->castAs<SubRegion>();
1353   } else {
1354     ElementCount = svalBuilder.makeIntVal(1, true);
1355     Region = Target.getAsRegion()->castAs<SubRegion>();
1356   }
1357 
1358   // Set the region's extent equal to the Size in Bytes.
1359   QualType ElementType = NE->getAllocatedType();
1360   ASTContext &AstContext = C.getASTContext();
1361   CharUnits TypeSize = AstContext.getTypeSizeInChars(ElementType);
1362 
1363   if (ElementCount.getAs<NonLoc>()) {
1364     DefinedOrUnknownSVal DynSize = getDynamicSize(State, Region, svalBuilder);
1365 
1366     // size in Bytes = ElementCount*TypeSize
1367     SVal SizeInBytes = svalBuilder.evalBinOpNN(
1368         State, BO_Mul, ElementCount.castAs<NonLoc>(),
1369         svalBuilder.makeArrayIndex(TypeSize.getQuantity()),
1370         svalBuilder.getArrayIndexType());
1371     DefinedOrUnknownSVal DynSizeMatchesSize = svalBuilder.evalEQ(
1372         State, DynSize, SizeInBytes.castAs<DefinedOrUnknownSVal>());
1373     State = State->assume(DynSizeMatchesSize, true);
1374   }
1375   return State;
1376 }
1377 
1378 void MallocChecker::checkPreStmt(const CXXDeleteExpr *DE,
1379                                  CheckerContext &C) const {
1380 
1381   if (!ChecksEnabled[CK_NewDeleteChecker])
1382     if (SymbolRef Sym = C.getSVal(DE->getArgument()).getAsSymbol())
1383       checkUseAfterFree(Sym, C, DE->getArgument());
1384 
1385   if (!isStandardNewDelete(DE->getOperatorDelete()))
1386     return;
1387 
1388   ProgramStateRef State = C.getState();
1389   bool IsKnownToBeAllocated;
1390   State = FreeMemAux(C, DE->getArgument(), DE, State,
1391                      /*Hold*/ false, IsKnownToBeAllocated,
1392                      (DE->isArrayForm() ? AF_CXXNewArray : AF_CXXNew));
1393 
1394   C.addTransition(State);
1395 }
1396 
1397 static bool isKnownDeallocObjCMethodName(const ObjCMethodCall &Call) {
1398   // If the first selector piece is one of the names below, assume that the
1399   // object takes ownership of the memory, promising to eventually deallocate it
1400   // with free().
1401   // Ex:  [NSData dataWithBytesNoCopy:bytes length:10];
1402   // (...unless a 'freeWhenDone' parameter is false, but that's checked later.)
1403   StringRef FirstSlot = Call.getSelector().getNameForSlot(0);
1404   return FirstSlot == "dataWithBytesNoCopy" ||
1405          FirstSlot == "initWithBytesNoCopy" ||
1406          FirstSlot == "initWithCharactersNoCopy";
1407 }
1408 
1409 static Optional<bool> getFreeWhenDoneArg(const ObjCMethodCall &Call) {
1410   Selector S = Call.getSelector();
1411 
1412   // FIXME: We should not rely on fully-constrained symbols being folded.
1413   for (unsigned i = 1; i < S.getNumArgs(); ++i)
1414     if (S.getNameForSlot(i).equals("freeWhenDone"))
1415       return !Call.getArgSVal(i).isZeroConstant();
1416 
1417   return None;
1418 }
1419 
1420 void MallocChecker::checkPostObjCMessage(const ObjCMethodCall &Call,
1421                                          CheckerContext &C) const {
1422   if (C.wasInlined)
1423     return;
1424 
1425   if (!isKnownDeallocObjCMethodName(Call))
1426     return;
1427 
1428   if (Optional<bool> FreeWhenDone = getFreeWhenDoneArg(Call))
1429     if (!*FreeWhenDone)
1430       return;
1431 
1432   if (Call.hasNonZeroCallbackArg())
1433     return;
1434 
1435   bool IsKnownToBeAllocatedMemory;
1436   ProgramStateRef State =
1437       FreeMemAux(C, Call.getArgExpr(0), Call.getOriginExpr(), C.getState(),
1438                  /*Hold=*/true, IsKnownToBeAllocatedMemory, AF_Malloc,
1439                  /*RetNullOnFailure=*/true);
1440 
1441   C.addTransition(State);
1442 }
1443 
1444 ProgramStateRef
1445 MallocChecker::MallocMemReturnsAttr(CheckerContext &C, const CallExpr *CE,
1446                                     const OwnershipAttr *Att,
1447                                     ProgramStateRef State) const {
1448   if (!State)
1449     return nullptr;
1450 
1451   if (Att->getModule()->getName() !=
1452       MemFunctionInfo.CD_malloc.getFunctionName())
1453     return nullptr;
1454 
1455   OwnershipAttr::args_iterator I = Att->args_begin(), E = Att->args_end();
1456   if (I != E) {
1457     return MallocMemAux(C, CE, CE->getArg(I->getASTIndex()), UndefinedVal(),
1458                         State, AF_Malloc);
1459   }
1460   return MallocMemAux(C, CE, UnknownVal(), UndefinedVal(), State, AF_Malloc);
1461 }
1462 
1463 ProgramStateRef MallocChecker::MallocMemAux(CheckerContext &C,
1464                                             const CallExpr *CE,
1465                                             const Expr *SizeEx, SVal Init,
1466                                             ProgramStateRef State,
1467                                             AllocationFamily Family) {
1468   if (!State)
1469     return nullptr;
1470 
1471   return MallocMemAux(C, CE, C.getSVal(SizeEx), Init, State, Family);
1472 }
1473 
1474 ProgramStateRef MallocChecker::MallocMemAux(CheckerContext &C,
1475                                             const CallExpr *CE, SVal Size,
1476                                             SVal Init, ProgramStateRef State,
1477                                             AllocationFamily Family) {
1478   if (!State)
1479     return nullptr;
1480 
1481   // We expect the malloc functions to return a pointer.
1482   if (!Loc::isLocType(CE->getType()))
1483     return nullptr;
1484 
1485   // Bind the return value to the symbolic value from the heap region.
1486   // TODO: We could rewrite post visit to eval call; 'malloc' does not have
1487   // side effects other than what we model here.
1488   unsigned Count = C.blockCount();
1489   SValBuilder &svalBuilder = C.getSValBuilder();
1490   const LocationContext *LCtx = C.getPredecessor()->getLocationContext();
1491   DefinedSVal RetVal = svalBuilder.getConjuredHeapSymbolVal(CE, LCtx, Count)
1492       .castAs<DefinedSVal>();
1493   State = State->BindExpr(CE, C.getLocationContext(), RetVal);
1494 
1495   // Fill the region with the initialization value.
1496   State = State->bindDefaultInitial(RetVal, Init, LCtx);
1497 
1498   // Set the region's extent equal to the Size parameter.
1499   const SymbolicRegion *R =
1500       dyn_cast_or_null<SymbolicRegion>(RetVal.getAsRegion());
1501   if (!R)
1502     return nullptr;
1503   if (Optional<DefinedOrUnknownSVal> DefinedSize =
1504           Size.getAs<DefinedOrUnknownSVal>()) {
1505     DefinedOrUnknownSVal DynSize = getDynamicSize(State, R, svalBuilder);
1506 
1507     DefinedOrUnknownSVal DynSizeMatchesSize =
1508         svalBuilder.evalEQ(State, DynSize, *DefinedSize);
1509 
1510     State = State->assume(DynSizeMatchesSize, true);
1511     assert(State);
1512   }
1513 
1514   return MallocUpdateRefState(C, CE, State, Family);
1515 }
1516 
1517 static ProgramStateRef MallocUpdateRefState(CheckerContext &C, const Expr *E,
1518                                             ProgramStateRef State,
1519                                             AllocationFamily Family,
1520                                             Optional<SVal> RetVal) {
1521   if (!State)
1522     return nullptr;
1523 
1524   // Get the return value.
1525   if (!RetVal)
1526     RetVal = C.getSVal(E);
1527 
1528   // We expect the malloc functions to return a pointer.
1529   if (!RetVal->getAs<Loc>())
1530     return nullptr;
1531 
1532   SymbolRef Sym = RetVal->getAsLocSymbol();
1533   // This is a return value of a function that was not inlined, such as malloc()
1534   // or new(). We've checked that in the caller. Therefore, it must be a symbol.
1535   assert(Sym);
1536 
1537   // Set the symbol's state to Allocated.
1538   return State->set<RegionState>(Sym, RefState::getAllocated(Family, E));
1539 }
1540 
1541 ProgramStateRef MallocChecker::FreeMemAttr(CheckerContext &C,
1542                                            const CallExpr *CE,
1543                                            const OwnershipAttr *Att,
1544                                            ProgramStateRef State) const {
1545   if (!State)
1546     return nullptr;
1547 
1548   if (Att->getModule()->getName() !=
1549       MemFunctionInfo.CD_malloc.getFunctionName())
1550     return nullptr;
1551 
1552   bool IsKnownToBeAllocated = false;
1553 
1554   for (const auto &Arg : Att->args()) {
1555     ProgramStateRef StateI =
1556         FreeMemAux(C, CE, State, Arg.getASTIndex(),
1557                    Att->getOwnKind() == OwnershipAttr::Holds,
1558                    IsKnownToBeAllocated, AF_Malloc);
1559     if (StateI)
1560       State = StateI;
1561   }
1562   return State;
1563 }
1564 
1565 ProgramStateRef MallocChecker::FreeMemAux(CheckerContext &C, const CallExpr *CE,
1566                                           ProgramStateRef State, unsigned Num,
1567                                           bool Hold, bool &IsKnownToBeAllocated,
1568                                           AllocationFamily Family,
1569                                           bool ReturnsNullOnFailure) const {
1570   if (!State)
1571     return nullptr;
1572 
1573   if (CE->getNumArgs() < (Num + 1))
1574     return nullptr;
1575 
1576   return FreeMemAux(C, CE->getArg(Num), CE, State, Hold, IsKnownToBeAllocated,
1577                     Family, ReturnsNullOnFailure);
1578 }
1579 
1580 /// Checks if the previous call to free on the given symbol failed - if free
1581 /// failed, returns true. Also, returns the corresponding return value symbol.
1582 static bool didPreviousFreeFail(ProgramStateRef State,
1583                                 SymbolRef Sym, SymbolRef &RetStatusSymbol) {
1584   const SymbolRef *Ret = State->get<FreeReturnValue>(Sym);
1585   if (Ret) {
1586     assert(*Ret && "We should not store the null return symbol");
1587     ConstraintManager &CMgr = State->getConstraintManager();
1588     ConditionTruthVal FreeFailed = CMgr.isNull(State, *Ret);
1589     RetStatusSymbol = *Ret;
1590     return FreeFailed.isConstrainedTrue();
1591   }
1592   return false;
1593 }
1594 
1595 static bool printMemFnName(raw_ostream &os, CheckerContext &C, const Expr *E) {
1596   if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
1597     // FIXME: This doesn't handle indirect calls.
1598     const FunctionDecl *FD = CE->getDirectCallee();
1599     if (!FD)
1600       return false;
1601 
1602     os << *FD;
1603     if (!FD->isOverloadedOperator())
1604       os << "()";
1605     return true;
1606   }
1607 
1608   if (const ObjCMessageExpr *Msg = dyn_cast<ObjCMessageExpr>(E)) {
1609     if (Msg->isInstanceMessage())
1610       os << "-";
1611     else
1612       os << "+";
1613     Msg->getSelector().print(os);
1614     return true;
1615   }
1616 
1617   if (const CXXNewExpr *NE = dyn_cast<CXXNewExpr>(E)) {
1618     os << "'"
1619        << getOperatorSpelling(NE->getOperatorNew()->getOverloadedOperator())
1620        << "'";
1621     return true;
1622   }
1623 
1624   if (const CXXDeleteExpr *DE = dyn_cast<CXXDeleteExpr>(E)) {
1625     os << "'"
1626        << getOperatorSpelling(DE->getOperatorDelete()->getOverloadedOperator())
1627        << "'";
1628     return true;
1629   }
1630 
1631   return false;
1632 }
1633 
1634 static void printExpectedAllocName(raw_ostream &os, AllocationFamily Family) {
1635 
1636   switch(Family) {
1637     case AF_Malloc: os << "malloc()"; return;
1638     case AF_CXXNew: os << "'new'"; return;
1639     case AF_CXXNewArray: os << "'new[]'"; return;
1640     case AF_IfNameIndex: os << "'if_nameindex()'"; return;
1641     case AF_InnerBuffer: os << "container-specific allocator"; return;
1642     case AF_Alloca:
1643     case AF_None: llvm_unreachable("not a deallocation expression");
1644   }
1645 }
1646 
1647 static void printExpectedDeallocName(raw_ostream &os, AllocationFamily Family) {
1648   switch(Family) {
1649     case AF_Malloc: os << "free()"; return;
1650     case AF_CXXNew: os << "'delete'"; return;
1651     case AF_CXXNewArray: os << "'delete[]'"; return;
1652     case AF_IfNameIndex: os << "'if_freenameindex()'"; return;
1653     case AF_InnerBuffer: os << "container-specific deallocator"; return;
1654     case AF_Alloca:
1655     case AF_None: llvm_unreachable("suspicious argument");
1656   }
1657 }
1658 
1659 ProgramStateRef MallocChecker::FreeMemAux(
1660     CheckerContext &C, const Expr *ArgExpr, const Expr *ParentExpr,
1661     ProgramStateRef State, bool Hold, bool &IsKnownToBeAllocated,
1662     AllocationFamily Family, bool ReturnsNullOnFailure) const {
1663 
1664   if (!State)
1665     return nullptr;
1666 
1667   SVal ArgVal = C.getSVal(ArgExpr);
1668   if (!ArgVal.getAs<DefinedOrUnknownSVal>())
1669     return nullptr;
1670   DefinedOrUnknownSVal location = ArgVal.castAs<DefinedOrUnknownSVal>();
1671 
1672   // Check for null dereferences.
1673   if (!location.getAs<Loc>())
1674     return nullptr;
1675 
1676   // The explicit NULL case, no operation is performed.
1677   ProgramStateRef notNullState, nullState;
1678   std::tie(notNullState, nullState) = State->assume(location);
1679   if (nullState && !notNullState)
1680     return nullptr;
1681 
1682   // Unknown values could easily be okay
1683   // Undefined values are handled elsewhere
1684   if (ArgVal.isUnknownOrUndef())
1685     return nullptr;
1686 
1687   const MemRegion *R = ArgVal.getAsRegion();
1688 
1689   // Nonlocs can't be freed, of course.
1690   // Non-region locations (labels and fixed addresses) also shouldn't be freed.
1691   if (!R) {
1692     // Exception:
1693     // If the macro ZERO_SIZE_PTR is defined, this could be a kernel source
1694     // code. In that case, the ZERO_SIZE_PTR defines a special value used for a
1695     // zero-sized memory block which is allowed to be freed, despite not being a
1696     // null pointer.
1697     if (Family != AF_Malloc || !isArgZERO_SIZE_PTR(State, C, ArgVal))
1698       ReportBadFree(C, ArgVal, ArgExpr->getSourceRange(), ParentExpr, Family);
1699     return nullptr;
1700   }
1701 
1702   R = R->StripCasts();
1703 
1704   // Blocks might show up as heap data, but should not be free()d
1705   if (isa<BlockDataRegion>(R)) {
1706     ReportBadFree(C, ArgVal, ArgExpr->getSourceRange(), ParentExpr, Family);
1707     return nullptr;
1708   }
1709 
1710   const MemSpaceRegion *MS = R->getMemorySpace();
1711 
1712   // Parameters, locals, statics, globals, and memory returned by
1713   // __builtin_alloca() shouldn't be freed.
1714   if (!(isa<UnknownSpaceRegion>(MS) || isa<HeapSpaceRegion>(MS))) {
1715     // FIXME: at the time this code was written, malloc() regions were
1716     // represented by conjured symbols, which are all in UnknownSpaceRegion.
1717     // This means that there isn't actually anything from HeapSpaceRegion
1718     // that should be freed, even though we allow it here.
1719     // Of course, free() can work on memory allocated outside the current
1720     // function, so UnknownSpaceRegion is always a possibility.
1721     // False negatives are better than false positives.
1722 
1723     if (isa<AllocaRegion>(R))
1724       ReportFreeAlloca(C, ArgVal, ArgExpr->getSourceRange());
1725     else
1726       ReportBadFree(C, ArgVal, ArgExpr->getSourceRange(), ParentExpr, Family);
1727 
1728     return nullptr;
1729   }
1730 
1731   const SymbolicRegion *SrBase = dyn_cast<SymbolicRegion>(R->getBaseRegion());
1732   // Various cases could lead to non-symbol values here.
1733   // For now, ignore them.
1734   if (!SrBase)
1735     return nullptr;
1736 
1737   SymbolRef SymBase = SrBase->getSymbol();
1738   const RefState *RsBase = State->get<RegionState>(SymBase);
1739   SymbolRef PreviousRetStatusSymbol = nullptr;
1740 
1741   IsKnownToBeAllocated =
1742       RsBase && (RsBase->isAllocated() || RsBase->isAllocatedOfSizeZero());
1743 
1744   if (RsBase) {
1745 
1746     // Memory returned by alloca() shouldn't be freed.
1747     if (RsBase->getAllocationFamily() == AF_Alloca) {
1748       ReportFreeAlloca(C, ArgVal, ArgExpr->getSourceRange());
1749       return nullptr;
1750     }
1751 
1752     // Check for double free first.
1753     if ((RsBase->isReleased() || RsBase->isRelinquished()) &&
1754         !didPreviousFreeFail(State, SymBase, PreviousRetStatusSymbol)) {
1755       ReportDoubleFree(C, ParentExpr->getSourceRange(), RsBase->isReleased(),
1756                        SymBase, PreviousRetStatusSymbol);
1757       return nullptr;
1758 
1759     // If the pointer is allocated or escaped, but we are now trying to free it,
1760     // check that the call to free is proper.
1761     } else if (RsBase->isAllocated() || RsBase->isAllocatedOfSizeZero() ||
1762                RsBase->isEscaped()) {
1763 
1764       // Check if an expected deallocation function matches the real one.
1765       bool DeallocMatchesAlloc = RsBase->getAllocationFamily() == Family;
1766       if (!DeallocMatchesAlloc) {
1767         ReportMismatchedDealloc(C, ArgExpr->getSourceRange(),
1768                                 ParentExpr, RsBase, SymBase, Hold);
1769         return nullptr;
1770       }
1771 
1772       // Check if the memory location being freed is the actual location
1773       // allocated, or an offset.
1774       RegionOffset Offset = R->getAsOffset();
1775       if (Offset.isValid() &&
1776           !Offset.hasSymbolicOffset() &&
1777           Offset.getOffset() != 0) {
1778         const Expr *AllocExpr = cast<Expr>(RsBase->getStmt());
1779         ReportOffsetFree(C, ArgVal, ArgExpr->getSourceRange(), ParentExpr,
1780                          Family, AllocExpr);
1781         return nullptr;
1782       }
1783     }
1784   }
1785 
1786   if (SymBase->getType()->isFunctionPointerType()) {
1787     ReportFunctionPointerFree(C, ArgVal, ArgExpr->getSourceRange(), ParentExpr,
1788                               Family);
1789     return nullptr;
1790   }
1791 
1792   // Clean out the info on previous call to free return info.
1793   State = State->remove<FreeReturnValue>(SymBase);
1794 
1795   // Keep track of the return value. If it is NULL, we will know that free
1796   // failed.
1797   if (ReturnsNullOnFailure) {
1798     SVal RetVal = C.getSVal(ParentExpr);
1799     SymbolRef RetStatusSymbol = RetVal.getAsSymbol();
1800     if (RetStatusSymbol) {
1801       C.getSymbolManager().addSymbolDependency(SymBase, RetStatusSymbol);
1802       State = State->set<FreeReturnValue>(SymBase, RetStatusSymbol);
1803     }
1804   }
1805 
1806   // If we don't know anything about this symbol, a free on it may be totally
1807   // valid. If this is the case, lets assume that the allocation family of the
1808   // freeing function is the same as the symbols allocation family, and go with
1809   // that.
1810   assert(!RsBase || (RsBase && RsBase->getAllocationFamily() == Family));
1811 
1812   // Normal free.
1813   if (Hold)
1814     return State->set<RegionState>(SymBase,
1815                                    RefState::getRelinquished(Family,
1816                                                              ParentExpr));
1817 
1818   return State->set<RegionState>(SymBase,
1819                                  RefState::getReleased(Family, ParentExpr));
1820 }
1821 
1822 Optional<MallocChecker::CheckKind>
1823 MallocChecker::getCheckIfTracked(AllocationFamily Family,
1824                                  bool IsALeakCheck) const {
1825   switch (Family) {
1826   case AF_Malloc:
1827   case AF_Alloca:
1828   case AF_IfNameIndex: {
1829     if (ChecksEnabled[CK_MallocChecker])
1830       return CK_MallocChecker;
1831     return None;
1832   }
1833   case AF_CXXNew:
1834   case AF_CXXNewArray: {
1835     if (IsALeakCheck) {
1836       if (ChecksEnabled[CK_NewDeleteLeaksChecker])
1837         return CK_NewDeleteLeaksChecker;
1838     }
1839     else {
1840       if (ChecksEnabled[CK_NewDeleteChecker])
1841         return CK_NewDeleteChecker;
1842     }
1843     return None;
1844   }
1845   case AF_InnerBuffer: {
1846     if (ChecksEnabled[CK_InnerPointerChecker])
1847       return CK_InnerPointerChecker;
1848     return None;
1849   }
1850   case AF_None: {
1851     llvm_unreachable("no family");
1852   }
1853   }
1854   llvm_unreachable("unhandled family");
1855 }
1856 
1857 Optional<MallocChecker::CheckKind>
1858 MallocChecker::getCheckIfTracked(CheckerContext &C, SymbolRef Sym,
1859                                  bool IsALeakCheck) const {
1860   if (C.getState()->contains<ReallocSizeZeroSymbols>(Sym))
1861     return CK_MallocChecker;
1862 
1863   const RefState *RS = C.getState()->get<RegionState>(Sym);
1864   assert(RS);
1865   return getCheckIfTracked(RS->getAllocationFamily(), IsALeakCheck);
1866 }
1867 
1868 bool MallocChecker::SummarizeValue(raw_ostream &os, SVal V) {
1869   if (Optional<nonloc::ConcreteInt> IntVal = V.getAs<nonloc::ConcreteInt>())
1870     os << "an integer (" << IntVal->getValue() << ")";
1871   else if (Optional<loc::ConcreteInt> ConstAddr = V.getAs<loc::ConcreteInt>())
1872     os << "a constant address (" << ConstAddr->getValue() << ")";
1873   else if (Optional<loc::GotoLabel> Label = V.getAs<loc::GotoLabel>())
1874     os << "the address of the label '" << Label->getLabel()->getName() << "'";
1875   else
1876     return false;
1877 
1878   return true;
1879 }
1880 
1881 bool MallocChecker::SummarizeRegion(raw_ostream &os,
1882                                     const MemRegion *MR) {
1883   switch (MR->getKind()) {
1884   case MemRegion::FunctionCodeRegionKind: {
1885     const NamedDecl *FD = cast<FunctionCodeRegion>(MR)->getDecl();
1886     if (FD)
1887       os << "the address of the function '" << *FD << '\'';
1888     else
1889       os << "the address of a function";
1890     return true;
1891   }
1892   case MemRegion::BlockCodeRegionKind:
1893     os << "block text";
1894     return true;
1895   case MemRegion::BlockDataRegionKind:
1896     // FIXME: where the block came from?
1897     os << "a block";
1898     return true;
1899   default: {
1900     const MemSpaceRegion *MS = MR->getMemorySpace();
1901 
1902     if (isa<StackLocalsSpaceRegion>(MS)) {
1903       const VarRegion *VR = dyn_cast<VarRegion>(MR);
1904       const VarDecl *VD;
1905       if (VR)
1906         VD = VR->getDecl();
1907       else
1908         VD = nullptr;
1909 
1910       if (VD)
1911         os << "the address of the local variable '" << VD->getName() << "'";
1912       else
1913         os << "the address of a local stack variable";
1914       return true;
1915     }
1916 
1917     if (isa<StackArgumentsSpaceRegion>(MS)) {
1918       const VarRegion *VR = dyn_cast<VarRegion>(MR);
1919       const VarDecl *VD;
1920       if (VR)
1921         VD = VR->getDecl();
1922       else
1923         VD = nullptr;
1924 
1925       if (VD)
1926         os << "the address of the parameter '" << VD->getName() << "'";
1927       else
1928         os << "the address of a parameter";
1929       return true;
1930     }
1931 
1932     if (isa<GlobalsSpaceRegion>(MS)) {
1933       const VarRegion *VR = dyn_cast<VarRegion>(MR);
1934       const VarDecl *VD;
1935       if (VR)
1936         VD = VR->getDecl();
1937       else
1938         VD = nullptr;
1939 
1940       if (VD) {
1941         if (VD->isStaticLocal())
1942           os << "the address of the static variable '" << VD->getName() << "'";
1943         else
1944           os << "the address of the global variable '" << VD->getName() << "'";
1945       } else
1946         os << "the address of a global variable";
1947       return true;
1948     }
1949 
1950     return false;
1951   }
1952   }
1953 }
1954 
1955 void MallocChecker::ReportBadFree(CheckerContext &C, SVal ArgVal,
1956                                   SourceRange Range, const Expr *DeallocExpr,
1957                                   AllocationFamily Family) const {
1958 
1959   if (!ChecksEnabled[CK_MallocChecker] &&
1960       !ChecksEnabled[CK_NewDeleteChecker])
1961     return;
1962 
1963   Optional<MallocChecker::CheckKind> CheckKind = getCheckIfTracked(Family);
1964   if (!CheckKind.hasValue())
1965     return;
1966 
1967   if (ExplodedNode *N = C.generateErrorNode()) {
1968     if (!BT_BadFree[*CheckKind])
1969       BT_BadFree[*CheckKind].reset(new BugType(
1970           CheckNames[*CheckKind], "Bad free", categories::MemoryError));
1971 
1972     SmallString<100> buf;
1973     llvm::raw_svector_ostream os(buf);
1974 
1975     const MemRegion *MR = ArgVal.getAsRegion();
1976     while (const ElementRegion *ER = dyn_cast_or_null<ElementRegion>(MR))
1977       MR = ER->getSuperRegion();
1978 
1979     os << "Argument to ";
1980     if (!printMemFnName(os, C, DeallocExpr))
1981       os << "deallocator";
1982 
1983     os << " is ";
1984     bool Summarized = MR ? SummarizeRegion(os, MR)
1985                          : SummarizeValue(os, ArgVal);
1986     if (Summarized)
1987       os << ", which is not memory allocated by ";
1988     else
1989       os << "not memory allocated by ";
1990 
1991     printExpectedAllocName(os, Family);
1992 
1993     auto R = std::make_unique<PathSensitiveBugReport>(*BT_BadFree[*CheckKind],
1994                                                       os.str(), N);
1995     R->markInteresting(MR);
1996     R->addRange(Range);
1997     C.emitReport(std::move(R));
1998   }
1999 }
2000 
2001 void MallocChecker::ReportFreeAlloca(CheckerContext &C, SVal ArgVal,
2002                                      SourceRange Range) const {
2003 
2004   Optional<MallocChecker::CheckKind> CheckKind;
2005 
2006   if (ChecksEnabled[CK_MallocChecker])
2007     CheckKind = CK_MallocChecker;
2008   else if (ChecksEnabled[CK_MismatchedDeallocatorChecker])
2009     CheckKind = CK_MismatchedDeallocatorChecker;
2010   else
2011     return;
2012 
2013   if (ExplodedNode *N = C.generateErrorNode()) {
2014     if (!BT_FreeAlloca[*CheckKind])
2015       BT_FreeAlloca[*CheckKind].reset(new BugType(
2016           CheckNames[*CheckKind], "Free alloca()", categories::MemoryError));
2017 
2018     auto R = std::make_unique<PathSensitiveBugReport>(
2019         *BT_FreeAlloca[*CheckKind],
2020         "Memory allocated by alloca() should not be deallocated", N);
2021     R->markInteresting(ArgVal.getAsRegion());
2022     R->addRange(Range);
2023     C.emitReport(std::move(R));
2024   }
2025 }
2026 
2027 void MallocChecker::ReportMismatchedDealloc(CheckerContext &C,
2028                                             SourceRange Range,
2029                                             const Expr *DeallocExpr,
2030                                             const RefState *RS,
2031                                             SymbolRef Sym,
2032                                             bool OwnershipTransferred) const {
2033 
2034   if (!ChecksEnabled[CK_MismatchedDeallocatorChecker])
2035     return;
2036 
2037   if (ExplodedNode *N = C.generateErrorNode()) {
2038     if (!BT_MismatchedDealloc)
2039       BT_MismatchedDealloc.reset(
2040           new BugType(CheckNames[CK_MismatchedDeallocatorChecker],
2041                       "Bad deallocator", categories::MemoryError));
2042 
2043     SmallString<100> buf;
2044     llvm::raw_svector_ostream os(buf);
2045 
2046     const Expr *AllocExpr = cast<Expr>(RS->getStmt());
2047     SmallString<20> AllocBuf;
2048     llvm::raw_svector_ostream AllocOs(AllocBuf);
2049     SmallString<20> DeallocBuf;
2050     llvm::raw_svector_ostream DeallocOs(DeallocBuf);
2051 
2052     if (OwnershipTransferred) {
2053       if (printMemFnName(DeallocOs, C, DeallocExpr))
2054         os << DeallocOs.str() << " cannot";
2055       else
2056         os << "Cannot";
2057 
2058       os << " take ownership of memory";
2059 
2060       if (printMemFnName(AllocOs, C, AllocExpr))
2061         os << " allocated by " << AllocOs.str();
2062     } else {
2063       os << "Memory";
2064       if (printMemFnName(AllocOs, C, AllocExpr))
2065         os << " allocated by " << AllocOs.str();
2066 
2067       os << " should be deallocated by ";
2068         printExpectedDeallocName(os, RS->getAllocationFamily());
2069 
2070         if (printMemFnName(DeallocOs, C, DeallocExpr))
2071           os << ", not " << DeallocOs.str();
2072     }
2073 
2074     auto R = std::make_unique<PathSensitiveBugReport>(*BT_MismatchedDealloc,
2075                                                       os.str(), N);
2076     R->markInteresting(Sym);
2077     R->addRange(Range);
2078     R->addVisitor(std::make_unique<MallocBugVisitor>(Sym));
2079     C.emitReport(std::move(R));
2080   }
2081 }
2082 
2083 void MallocChecker::ReportOffsetFree(CheckerContext &C, SVal ArgVal,
2084                                      SourceRange Range, const Expr *DeallocExpr,
2085                                      AllocationFamily Family,
2086                                      const Expr *AllocExpr) const {
2087 
2088   if (!ChecksEnabled[CK_MallocChecker] &&
2089       !ChecksEnabled[CK_NewDeleteChecker])
2090     return;
2091 
2092   Optional<MallocChecker::CheckKind> CheckKind = getCheckIfTracked(Family);
2093   if (!CheckKind.hasValue())
2094     return;
2095 
2096   ExplodedNode *N = C.generateErrorNode();
2097   if (!N)
2098     return;
2099 
2100   if (!BT_OffsetFree[*CheckKind])
2101     BT_OffsetFree[*CheckKind].reset(new BugType(
2102         CheckNames[*CheckKind], "Offset free", categories::MemoryError));
2103 
2104   SmallString<100> buf;
2105   llvm::raw_svector_ostream os(buf);
2106   SmallString<20> AllocNameBuf;
2107   llvm::raw_svector_ostream AllocNameOs(AllocNameBuf);
2108 
2109   const MemRegion *MR = ArgVal.getAsRegion();
2110   assert(MR && "Only MemRegion based symbols can have offset free errors");
2111 
2112   RegionOffset Offset = MR->getAsOffset();
2113   assert((Offset.isValid() &&
2114           !Offset.hasSymbolicOffset() &&
2115           Offset.getOffset() != 0) &&
2116          "Only symbols with a valid offset can have offset free errors");
2117 
2118   int offsetBytes = Offset.getOffset() / C.getASTContext().getCharWidth();
2119 
2120   os << "Argument to ";
2121   if (!printMemFnName(os, C, DeallocExpr))
2122     os << "deallocator";
2123   os << " is offset by "
2124      << offsetBytes
2125      << " "
2126      << ((abs(offsetBytes) > 1) ? "bytes" : "byte")
2127      << " from the start of ";
2128   if (AllocExpr && printMemFnName(AllocNameOs, C, AllocExpr))
2129     os << "memory allocated by " << AllocNameOs.str();
2130   else
2131     os << "allocated memory";
2132 
2133   auto R = std::make_unique<PathSensitiveBugReport>(*BT_OffsetFree[*CheckKind],
2134                                                     os.str(), N);
2135   R->markInteresting(MR->getBaseRegion());
2136   R->addRange(Range);
2137   C.emitReport(std::move(R));
2138 }
2139 
2140 void MallocChecker::ReportUseAfterFree(CheckerContext &C, SourceRange Range,
2141                                        SymbolRef Sym) const {
2142 
2143   if (!ChecksEnabled[CK_MallocChecker] &&
2144       !ChecksEnabled[CK_NewDeleteChecker] &&
2145       !ChecksEnabled[CK_InnerPointerChecker])
2146     return;
2147 
2148   Optional<MallocChecker::CheckKind> CheckKind = getCheckIfTracked(C, Sym);
2149   if (!CheckKind.hasValue())
2150     return;
2151 
2152   if (ExplodedNode *N = C.generateErrorNode()) {
2153     if (!BT_UseFree[*CheckKind])
2154       BT_UseFree[*CheckKind].reset(new BugType(
2155           CheckNames[*CheckKind], "Use-after-free", categories::MemoryError));
2156 
2157     AllocationFamily AF =
2158         C.getState()->get<RegionState>(Sym)->getAllocationFamily();
2159 
2160     auto R = std::make_unique<PathSensitiveBugReport>(
2161         *BT_UseFree[*CheckKind],
2162         AF == AF_InnerBuffer
2163             ? "Inner pointer of container used after re/deallocation"
2164             : "Use of memory after it is freed",
2165         N);
2166 
2167     R->markInteresting(Sym);
2168     R->addRange(Range);
2169     R->addVisitor(std::make_unique<MallocBugVisitor>(Sym));
2170 
2171     if (AF == AF_InnerBuffer)
2172       R->addVisitor(allocation_state::getInnerPointerBRVisitor(Sym));
2173 
2174     C.emitReport(std::move(R));
2175   }
2176 }
2177 
2178 void MallocChecker::ReportDoubleFree(CheckerContext &C, SourceRange Range,
2179                                      bool Released, SymbolRef Sym,
2180                                      SymbolRef PrevSym) const {
2181 
2182   if (!ChecksEnabled[CK_MallocChecker] &&
2183       !ChecksEnabled[CK_NewDeleteChecker])
2184     return;
2185 
2186   Optional<MallocChecker::CheckKind> CheckKind = getCheckIfTracked(C, Sym);
2187   if (!CheckKind.hasValue())
2188     return;
2189 
2190   if (ExplodedNode *N = C.generateErrorNode()) {
2191     if (!BT_DoubleFree[*CheckKind])
2192       BT_DoubleFree[*CheckKind].reset(new BugType(
2193           CheckNames[*CheckKind], "Double free", categories::MemoryError));
2194 
2195     auto R = std::make_unique<PathSensitiveBugReport>(
2196         *BT_DoubleFree[*CheckKind],
2197         (Released ? "Attempt to free released memory"
2198                   : "Attempt to free non-owned memory"),
2199         N);
2200     R->addRange(Range);
2201     R->markInteresting(Sym);
2202     if (PrevSym)
2203       R->markInteresting(PrevSym);
2204     R->addVisitor(std::make_unique<MallocBugVisitor>(Sym));
2205     C.emitReport(std::move(R));
2206   }
2207 }
2208 
2209 void MallocChecker::ReportDoubleDelete(CheckerContext &C, SymbolRef Sym) const {
2210 
2211   if (!ChecksEnabled[CK_NewDeleteChecker])
2212     return;
2213 
2214   Optional<MallocChecker::CheckKind> CheckKind = getCheckIfTracked(C, Sym);
2215   if (!CheckKind.hasValue())
2216     return;
2217 
2218   if (ExplodedNode *N = C.generateErrorNode()) {
2219     if (!BT_DoubleDelete)
2220       BT_DoubleDelete.reset(new BugType(CheckNames[CK_NewDeleteChecker],
2221                                         "Double delete",
2222                                         categories::MemoryError));
2223 
2224     auto R = std::make_unique<PathSensitiveBugReport>(
2225         *BT_DoubleDelete, "Attempt to delete released memory", N);
2226 
2227     R->markInteresting(Sym);
2228     R->addVisitor(std::make_unique<MallocBugVisitor>(Sym));
2229     C.emitReport(std::move(R));
2230   }
2231 }
2232 
2233 void MallocChecker::ReportUseZeroAllocated(CheckerContext &C,
2234                                            SourceRange Range,
2235                                            SymbolRef Sym) const {
2236 
2237   if (!ChecksEnabled[CK_MallocChecker] &&
2238       !ChecksEnabled[CK_NewDeleteChecker])
2239     return;
2240 
2241   Optional<MallocChecker::CheckKind> CheckKind = getCheckIfTracked(C, Sym);
2242 
2243   if (!CheckKind.hasValue())
2244     return;
2245 
2246   if (ExplodedNode *N = C.generateErrorNode()) {
2247     if (!BT_UseZerroAllocated[*CheckKind])
2248       BT_UseZerroAllocated[*CheckKind].reset(
2249           new BugType(CheckNames[*CheckKind], "Use of zero allocated",
2250                       categories::MemoryError));
2251 
2252     auto R = std::make_unique<PathSensitiveBugReport>(
2253         *BT_UseZerroAllocated[*CheckKind], "Use of zero-allocated memory", N);
2254 
2255     R->addRange(Range);
2256     if (Sym) {
2257       R->markInteresting(Sym);
2258       R->addVisitor(std::make_unique<MallocBugVisitor>(Sym));
2259     }
2260     C.emitReport(std::move(R));
2261   }
2262 }
2263 
2264 void MallocChecker::ReportFunctionPointerFree(CheckerContext &C, SVal ArgVal,
2265                                               SourceRange Range,
2266                                               const Expr *FreeExpr,
2267                                               AllocationFamily Family) const {
2268   if (!ChecksEnabled[CK_MallocChecker])
2269     return;
2270 
2271   Optional<MallocChecker::CheckKind> CheckKind = getCheckIfTracked(Family);
2272   if (!CheckKind.hasValue())
2273     return;
2274 
2275   if (ExplodedNode *N = C.generateErrorNode()) {
2276     if (!BT_BadFree[*CheckKind])
2277       BT_BadFree[*CheckKind].reset(new BugType(
2278           CheckNames[*CheckKind], "Bad free", categories::MemoryError));
2279 
2280     SmallString<100> Buf;
2281     llvm::raw_svector_ostream Os(Buf);
2282 
2283     const MemRegion *MR = ArgVal.getAsRegion();
2284     while (const ElementRegion *ER = dyn_cast_or_null<ElementRegion>(MR))
2285       MR = ER->getSuperRegion();
2286 
2287     Os << "Argument to ";
2288     if (!printMemFnName(Os, C, FreeExpr))
2289       Os << "deallocator";
2290 
2291     Os << " is a function pointer";
2292 
2293     auto R = std::make_unique<PathSensitiveBugReport>(*BT_BadFree[*CheckKind],
2294                                                       Os.str(), N);
2295     R->markInteresting(MR);
2296     R->addRange(Range);
2297     C.emitReport(std::move(R));
2298   }
2299 }
2300 
2301 ProgramStateRef
2302 MallocChecker::ReallocMemAux(CheckerContext &C, const CallExpr *CE,
2303                              bool ShouldFreeOnFail, ProgramStateRef State,
2304                              AllocationFamily Family, bool SuffixWithN) const {
2305   if (!State)
2306     return nullptr;
2307 
2308   if (SuffixWithN && CE->getNumArgs() < 3)
2309     return nullptr;
2310   else if (CE->getNumArgs() < 2)
2311     return nullptr;
2312 
2313   const Expr *arg0Expr = CE->getArg(0);
2314   SVal Arg0Val = C.getSVal(arg0Expr);
2315   if (!Arg0Val.getAs<DefinedOrUnknownSVal>())
2316     return nullptr;
2317   DefinedOrUnknownSVal arg0Val = Arg0Val.castAs<DefinedOrUnknownSVal>();
2318 
2319   SValBuilder &svalBuilder = C.getSValBuilder();
2320 
2321   DefinedOrUnknownSVal PtrEQ =
2322     svalBuilder.evalEQ(State, arg0Val, svalBuilder.makeNull());
2323 
2324   // Get the size argument.
2325   const Expr *Arg1 = CE->getArg(1);
2326 
2327   // Get the value of the size argument.
2328   SVal TotalSize = C.getSVal(Arg1);
2329   if (SuffixWithN)
2330     TotalSize = evalMulForBufferSize(C, Arg1, CE->getArg(2));
2331   if (!TotalSize.getAs<DefinedOrUnknownSVal>())
2332     return nullptr;
2333 
2334   // Compare the size argument to 0.
2335   DefinedOrUnknownSVal SizeZero =
2336     svalBuilder.evalEQ(State, TotalSize.castAs<DefinedOrUnknownSVal>(),
2337                        svalBuilder.makeIntValWithPtrWidth(0, false));
2338 
2339   ProgramStateRef StatePtrIsNull, StatePtrNotNull;
2340   std::tie(StatePtrIsNull, StatePtrNotNull) = State->assume(PtrEQ);
2341   ProgramStateRef StateSizeIsZero, StateSizeNotZero;
2342   std::tie(StateSizeIsZero, StateSizeNotZero) = State->assume(SizeZero);
2343   // We only assume exceptional states if they are definitely true; if the
2344   // state is under-constrained, assume regular realloc behavior.
2345   bool PrtIsNull = StatePtrIsNull && !StatePtrNotNull;
2346   bool SizeIsZero = StateSizeIsZero && !StateSizeNotZero;
2347 
2348   // If the ptr is NULL and the size is not 0, the call is equivalent to
2349   // malloc(size).
2350   if (PrtIsNull && !SizeIsZero) {
2351     ProgramStateRef stateMalloc =
2352         MallocMemAux(C, CE, TotalSize, UndefinedVal(), StatePtrIsNull, Family);
2353     return stateMalloc;
2354   }
2355 
2356   if (PrtIsNull && SizeIsZero)
2357     return State;
2358 
2359   // Get the from and to pointer symbols as in toPtr = realloc(fromPtr, size).
2360   assert(!PrtIsNull);
2361   SymbolRef FromPtr = arg0Val.getAsSymbol();
2362   SVal RetVal = C.getSVal(CE);
2363   SymbolRef ToPtr = RetVal.getAsSymbol();
2364   if (!FromPtr || !ToPtr)
2365     return nullptr;
2366 
2367   bool IsKnownToBeAllocated = false;
2368 
2369   // If the size is 0, free the memory.
2370   if (SizeIsZero)
2371     // The semantics of the return value are:
2372     // If size was equal to 0, either NULL or a pointer suitable to be passed
2373     // to free() is returned. We just free the input pointer and do not add
2374     // any constrains on the output pointer.
2375     if (ProgramStateRef stateFree = FreeMemAux(C, CE, StateSizeIsZero, 0, false,
2376                                                IsKnownToBeAllocated, Family))
2377       return stateFree;
2378 
2379   // Default behavior.
2380   if (ProgramStateRef stateFree =
2381           FreeMemAux(C, CE, State, 0, false, IsKnownToBeAllocated, Family)) {
2382 
2383     ProgramStateRef stateRealloc =
2384         MallocMemAux(C, CE, TotalSize, UnknownVal(), stateFree, Family);
2385     if (!stateRealloc)
2386       return nullptr;
2387 
2388     OwnershipAfterReallocKind Kind = OAR_ToBeFreedAfterFailure;
2389     if (ShouldFreeOnFail)
2390       Kind = OAR_FreeOnFailure;
2391     else if (!IsKnownToBeAllocated)
2392       Kind = OAR_DoNotTrackAfterFailure;
2393 
2394     // Record the info about the reallocated symbol so that we could properly
2395     // process failed reallocation.
2396     stateRealloc = stateRealloc->set<ReallocPairs>(ToPtr,
2397                                                    ReallocPair(FromPtr, Kind));
2398     // The reallocated symbol should stay alive for as long as the new symbol.
2399     C.getSymbolManager().addSymbolDependency(ToPtr, FromPtr);
2400     return stateRealloc;
2401   }
2402   return nullptr;
2403 }
2404 
2405 ProgramStateRef MallocChecker::CallocMem(CheckerContext &C, const CallExpr *CE,
2406                                          ProgramStateRef State) {
2407   if (!State)
2408     return nullptr;
2409 
2410   if (CE->getNumArgs() < 2)
2411     return nullptr;
2412 
2413   SValBuilder &svalBuilder = C.getSValBuilder();
2414   SVal zeroVal = svalBuilder.makeZeroVal(svalBuilder.getContext().CharTy);
2415   SVal TotalSize = evalMulForBufferSize(C, CE->getArg(0), CE->getArg(1));
2416 
2417   return MallocMemAux(C, CE, TotalSize, zeroVal, State, AF_Malloc);
2418 }
2419 
2420 MallocChecker::LeakInfo MallocChecker::getAllocationSite(const ExplodedNode *N,
2421                                                          SymbolRef Sym,
2422                                                          CheckerContext &C) {
2423   const LocationContext *LeakContext = N->getLocationContext();
2424   // Walk the ExplodedGraph backwards and find the first node that referred to
2425   // the tracked symbol.
2426   const ExplodedNode *AllocNode = N;
2427   const MemRegion *ReferenceRegion = nullptr;
2428 
2429   while (N) {
2430     ProgramStateRef State = N->getState();
2431     if (!State->get<RegionState>(Sym))
2432       break;
2433 
2434     // Find the most recent expression bound to the symbol in the current
2435     // context.
2436     if (!ReferenceRegion) {
2437       if (const MemRegion *MR = C.getLocationRegionIfPostStore(N)) {
2438         SVal Val = State->getSVal(MR);
2439         if (Val.getAsLocSymbol() == Sym) {
2440           const VarRegion *VR = MR->getBaseRegion()->getAs<VarRegion>();
2441           // Do not show local variables belonging to a function other than
2442           // where the error is reported.
2443           if (!VR || (VR->getStackFrame() == LeakContext->getStackFrame()))
2444             ReferenceRegion = MR;
2445         }
2446       }
2447     }
2448 
2449     // Allocation node, is the last node in the current or parent context in
2450     // which the symbol was tracked.
2451     const LocationContext *NContext = N->getLocationContext();
2452     if (NContext == LeakContext ||
2453         NContext->isParentOf(LeakContext))
2454       AllocNode = N;
2455     N = N->pred_empty() ? nullptr : *(N->pred_begin());
2456   }
2457 
2458   return LeakInfo(AllocNode, ReferenceRegion);
2459 }
2460 
2461 void MallocChecker::reportLeak(SymbolRef Sym, ExplodedNode *N,
2462                                CheckerContext &C) const {
2463 
2464   if (!ChecksEnabled[CK_MallocChecker] &&
2465       !ChecksEnabled[CK_NewDeleteLeaksChecker])
2466     return;
2467 
2468   const RefState *RS = C.getState()->get<RegionState>(Sym);
2469   assert(RS && "cannot leak an untracked symbol");
2470   AllocationFamily Family = RS->getAllocationFamily();
2471 
2472   if (Family == AF_Alloca)
2473     return;
2474 
2475   Optional<MallocChecker::CheckKind>
2476       CheckKind = getCheckIfTracked(Family, true);
2477 
2478   if (!CheckKind.hasValue())
2479     return;
2480 
2481   assert(N);
2482   if (!BT_Leak[*CheckKind]) {
2483     // Leaks should not be reported if they are post-dominated by a sink:
2484     // (1) Sinks are higher importance bugs.
2485     // (2) NoReturnFunctionChecker uses sink nodes to represent paths ending
2486     //     with __noreturn functions such as assert() or exit(). We choose not
2487     //     to report leaks on such paths.
2488     BT_Leak[*CheckKind].reset(new BugType(CheckNames[*CheckKind], "Memory leak",
2489                                           categories::MemoryError,
2490                                           /*SuppressOnSink=*/true));
2491   }
2492 
2493   // Most bug reports are cached at the location where they occurred.
2494   // With leaks, we want to unique them by the location where they were
2495   // allocated, and only report a single path.
2496   PathDiagnosticLocation LocUsedForUniqueing;
2497   const ExplodedNode *AllocNode = nullptr;
2498   const MemRegion *Region = nullptr;
2499   std::tie(AllocNode, Region) = getAllocationSite(N, Sym, C);
2500 
2501   const Stmt *AllocationStmt = AllocNode->getStmtForDiagnostics();
2502   if (AllocationStmt)
2503     LocUsedForUniqueing = PathDiagnosticLocation::createBegin(AllocationStmt,
2504                                               C.getSourceManager(),
2505                                               AllocNode->getLocationContext());
2506 
2507   SmallString<200> buf;
2508   llvm::raw_svector_ostream os(buf);
2509   if (Region && Region->canPrintPretty()) {
2510     os << "Potential leak of memory pointed to by ";
2511     Region->printPretty(os);
2512   } else {
2513     os << "Potential memory leak";
2514   }
2515 
2516   auto R = std::make_unique<PathSensitiveBugReport>(
2517       *BT_Leak[*CheckKind], os.str(), N, LocUsedForUniqueing,
2518       AllocNode->getLocationContext()->getDecl());
2519   R->markInteresting(Sym);
2520   R->addVisitor(std::make_unique<MallocBugVisitor>(Sym, true));
2521   C.emitReport(std::move(R));
2522 }
2523 
2524 void MallocChecker::checkDeadSymbols(SymbolReaper &SymReaper,
2525                                      CheckerContext &C) const
2526 {
2527   ProgramStateRef state = C.getState();
2528   RegionStateTy OldRS = state->get<RegionState>();
2529   RegionStateTy::Factory &F = state->get_context<RegionState>();
2530 
2531   RegionStateTy RS = OldRS;
2532   SmallVector<SymbolRef, 2> Errors;
2533   for (RegionStateTy::iterator I = RS.begin(), E = RS.end(); I != E; ++I) {
2534     if (SymReaper.isDead(I->first)) {
2535       if (I->second.isAllocated() || I->second.isAllocatedOfSizeZero())
2536         Errors.push_back(I->first);
2537       // Remove the dead symbol from the map.
2538       RS = F.remove(RS, I->first);
2539     }
2540   }
2541 
2542   if (RS == OldRS) {
2543     // We shouldn't have touched other maps yet.
2544     assert(state->get<ReallocPairs>() ==
2545            C.getState()->get<ReallocPairs>());
2546     assert(state->get<FreeReturnValue>() ==
2547            C.getState()->get<FreeReturnValue>());
2548     return;
2549   }
2550 
2551   // Cleanup the Realloc Pairs Map.
2552   ReallocPairsTy RP = state->get<ReallocPairs>();
2553   for (ReallocPairsTy::iterator I = RP.begin(), E = RP.end(); I != E; ++I) {
2554     if (SymReaper.isDead(I->first) ||
2555         SymReaper.isDead(I->second.ReallocatedSym)) {
2556       state = state->remove<ReallocPairs>(I->first);
2557     }
2558   }
2559 
2560   // Cleanup the FreeReturnValue Map.
2561   FreeReturnValueTy FR = state->get<FreeReturnValue>();
2562   for (FreeReturnValueTy::iterator I = FR.begin(), E = FR.end(); I != E; ++I) {
2563     if (SymReaper.isDead(I->first) ||
2564         SymReaper.isDead(I->second)) {
2565       state = state->remove<FreeReturnValue>(I->first);
2566     }
2567   }
2568 
2569   // Generate leak node.
2570   ExplodedNode *N = C.getPredecessor();
2571   if (!Errors.empty()) {
2572     static CheckerProgramPointTag Tag("MallocChecker", "DeadSymbolsLeak");
2573     N = C.generateNonFatalErrorNode(C.getState(), &Tag);
2574     if (N) {
2575       for (SmallVectorImpl<SymbolRef>::iterator
2576            I = Errors.begin(), E = Errors.end(); I != E; ++I) {
2577         reportLeak(*I, N, C);
2578       }
2579     }
2580   }
2581 
2582   C.addTransition(state->set<RegionState>(RS), N);
2583 }
2584 
2585 void MallocChecker::checkPreCall(const CallEvent &Call,
2586                                  CheckerContext &C) const {
2587 
2588   if (const CXXDestructorCall *DC = dyn_cast<CXXDestructorCall>(&Call)) {
2589     SymbolRef Sym = DC->getCXXThisVal().getAsSymbol();
2590     if (!Sym || checkDoubleDelete(Sym, C))
2591       return;
2592   }
2593 
2594   // We will check for double free in the post visit.
2595   if (const AnyFunctionCall *FC = dyn_cast<AnyFunctionCall>(&Call)) {
2596     const FunctionDecl *FD = FC->getDecl();
2597     if (!FD)
2598       return;
2599 
2600     if (ChecksEnabled[CK_MallocChecker] &&
2601         (MemFunctionInfo.isCMemFreeFunction(Call)))
2602       return;
2603   }
2604 
2605   // Check if the callee of a method is deleted.
2606   if (const CXXInstanceCall *CC = dyn_cast<CXXInstanceCall>(&Call)) {
2607     SymbolRef Sym = CC->getCXXThisVal().getAsSymbol();
2608     if (!Sym || checkUseAfterFree(Sym, C, CC->getCXXThisExpr()))
2609       return;
2610   }
2611 
2612   // Check arguments for being used after free.
2613   for (unsigned I = 0, E = Call.getNumArgs(); I != E; ++I) {
2614     SVal ArgSVal = Call.getArgSVal(I);
2615     if (ArgSVal.getAs<Loc>()) {
2616       SymbolRef Sym = ArgSVal.getAsSymbol();
2617       if (!Sym)
2618         continue;
2619       if (checkUseAfterFree(Sym, C, Call.getArgExpr(I)))
2620         return;
2621     }
2622   }
2623 }
2624 
2625 void MallocChecker::checkPreStmt(const ReturnStmt *S,
2626                                  CheckerContext &C) const {
2627   checkEscapeOnReturn(S, C);
2628 }
2629 
2630 // In the CFG, automatic destructors come after the return statement.
2631 // This callback checks for returning memory that is freed by automatic
2632 // destructors, as those cannot be reached in checkPreStmt().
2633 void MallocChecker::checkEndFunction(const ReturnStmt *S,
2634                                      CheckerContext &C) const {
2635   checkEscapeOnReturn(S, C);
2636 }
2637 
2638 void MallocChecker::checkEscapeOnReturn(const ReturnStmt *S,
2639                                         CheckerContext &C) const {
2640   if (!S)
2641     return;
2642 
2643   const Expr *E = S->getRetValue();
2644   if (!E)
2645     return;
2646 
2647   // Check if we are returning a symbol.
2648   ProgramStateRef State = C.getState();
2649   SVal RetVal = C.getSVal(E);
2650   SymbolRef Sym = RetVal.getAsSymbol();
2651   if (!Sym)
2652     // If we are returning a field of the allocated struct or an array element,
2653     // the callee could still free the memory.
2654     // TODO: This logic should be a part of generic symbol escape callback.
2655     if (const MemRegion *MR = RetVal.getAsRegion())
2656       if (isa<FieldRegion>(MR) || isa<ElementRegion>(MR))
2657         if (const SymbolicRegion *BMR =
2658               dyn_cast<SymbolicRegion>(MR->getBaseRegion()))
2659           Sym = BMR->getSymbol();
2660 
2661   // Check if we are returning freed memory.
2662   if (Sym)
2663     checkUseAfterFree(Sym, C, E);
2664 }
2665 
2666 // TODO: Blocks should be either inlined or should call invalidate regions
2667 // upon invocation. After that's in place, special casing here will not be
2668 // needed.
2669 void MallocChecker::checkPostStmt(const BlockExpr *BE,
2670                                   CheckerContext &C) const {
2671 
2672   // Scan the BlockDecRefExprs for any object the retain count checker
2673   // may be tracking.
2674   if (!BE->getBlockDecl()->hasCaptures())
2675     return;
2676 
2677   ProgramStateRef state = C.getState();
2678   const BlockDataRegion *R =
2679     cast<BlockDataRegion>(C.getSVal(BE).getAsRegion());
2680 
2681   BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(),
2682                                             E = R->referenced_vars_end();
2683 
2684   if (I == E)
2685     return;
2686 
2687   SmallVector<const MemRegion*, 10> Regions;
2688   const LocationContext *LC = C.getLocationContext();
2689   MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager();
2690 
2691   for ( ; I != E; ++I) {
2692     const VarRegion *VR = I.getCapturedRegion();
2693     if (VR->getSuperRegion() == R) {
2694       VR = MemMgr.getVarRegion(VR->getDecl(), LC);
2695     }
2696     Regions.push_back(VR);
2697   }
2698 
2699   state =
2700     state->scanReachableSymbols<StopTrackingCallback>(Regions).getState();
2701   C.addTransition(state);
2702 }
2703 
2704 static bool isReleased(SymbolRef Sym, CheckerContext &C) {
2705   assert(Sym);
2706   const RefState *RS = C.getState()->get<RegionState>(Sym);
2707   return (RS && RS->isReleased());
2708 }
2709 
2710 bool MallocChecker::suppressDeallocationsInSuspiciousContexts(
2711     const CallExpr *CE, CheckerContext &C) const {
2712   if (CE->getNumArgs() == 0)
2713     return false;
2714 
2715   StringRef FunctionStr = "";
2716   if (const auto *FD = dyn_cast<FunctionDecl>(C.getStackFrame()->getDecl()))
2717     if (const Stmt *Body = FD->getBody())
2718       if (Body->getBeginLoc().isValid())
2719         FunctionStr =
2720             Lexer::getSourceText(CharSourceRange::getTokenRange(
2721                                      {FD->getBeginLoc(), Body->getBeginLoc()}),
2722                                  C.getSourceManager(), C.getLangOpts());
2723 
2724   // We do not model the Integer Set Library's retain-count based allocation.
2725   if (!FunctionStr.contains("__isl_"))
2726     return false;
2727 
2728   ProgramStateRef State = C.getState();
2729 
2730   for (const Expr *Arg : CE->arguments())
2731     if (SymbolRef Sym = C.getSVal(Arg).getAsSymbol())
2732       if (const RefState *RS = State->get<RegionState>(Sym))
2733         State = State->set<RegionState>(Sym, RefState::getEscaped(RS));
2734 
2735   C.addTransition(State);
2736   return true;
2737 }
2738 
2739 bool MallocChecker::checkUseAfterFree(SymbolRef Sym, CheckerContext &C,
2740                                       const Stmt *S) const {
2741 
2742   if (isReleased(Sym, C)) {
2743     ReportUseAfterFree(C, S->getSourceRange(), Sym);
2744     return true;
2745   }
2746 
2747   return false;
2748 }
2749 
2750 void MallocChecker::checkUseZeroAllocated(SymbolRef Sym, CheckerContext &C,
2751                                           const Stmt *S) const {
2752   assert(Sym);
2753 
2754   if (const RefState *RS = C.getState()->get<RegionState>(Sym)) {
2755     if (RS->isAllocatedOfSizeZero())
2756       ReportUseZeroAllocated(C, RS->getStmt()->getSourceRange(), Sym);
2757   }
2758   else if (C.getState()->contains<ReallocSizeZeroSymbols>(Sym)) {
2759     ReportUseZeroAllocated(C, S->getSourceRange(), Sym);
2760   }
2761 }
2762 
2763 bool MallocChecker::checkDoubleDelete(SymbolRef Sym, CheckerContext &C) const {
2764 
2765   if (isReleased(Sym, C)) {
2766     ReportDoubleDelete(C, Sym);
2767     return true;
2768   }
2769   return false;
2770 }
2771 
2772 // Check if the location is a freed symbolic region.
2773 void MallocChecker::checkLocation(SVal l, bool isLoad, const Stmt *S,
2774                                   CheckerContext &C) const {
2775   SymbolRef Sym = l.getLocSymbolInBase();
2776   if (Sym) {
2777     checkUseAfterFree(Sym, C, S);
2778     checkUseZeroAllocated(Sym, C, S);
2779   }
2780 }
2781 
2782 // If a symbolic region is assumed to NULL (or another constant), stop tracking
2783 // it - assuming that allocation failed on this path.
2784 ProgramStateRef MallocChecker::evalAssume(ProgramStateRef state,
2785                                               SVal Cond,
2786                                               bool Assumption) const {
2787   RegionStateTy RS = state->get<RegionState>();
2788   for (RegionStateTy::iterator I = RS.begin(), E = RS.end(); I != E; ++I) {
2789     // If the symbol is assumed to be NULL, remove it from consideration.
2790     ConstraintManager &CMgr = state->getConstraintManager();
2791     ConditionTruthVal AllocFailed = CMgr.isNull(state, I.getKey());
2792     if (AllocFailed.isConstrainedTrue())
2793       state = state->remove<RegionState>(I.getKey());
2794   }
2795 
2796   // Realloc returns 0 when reallocation fails, which means that we should
2797   // restore the state of the pointer being reallocated.
2798   ReallocPairsTy RP = state->get<ReallocPairs>();
2799   for (ReallocPairsTy::iterator I = RP.begin(), E = RP.end(); I != E; ++I) {
2800     // If the symbol is assumed to be NULL, remove it from consideration.
2801     ConstraintManager &CMgr = state->getConstraintManager();
2802     ConditionTruthVal AllocFailed = CMgr.isNull(state, I.getKey());
2803     if (!AllocFailed.isConstrainedTrue())
2804       continue;
2805 
2806     SymbolRef ReallocSym = I.getData().ReallocatedSym;
2807     if (const RefState *RS = state->get<RegionState>(ReallocSym)) {
2808       if (RS->isReleased()) {
2809         switch (I.getData().Kind) {
2810         case OAR_ToBeFreedAfterFailure:
2811           state = state->set<RegionState>(ReallocSym,
2812               RefState::getAllocated(RS->getAllocationFamily(), RS->getStmt()));
2813           break;
2814         case OAR_DoNotTrackAfterFailure:
2815           state = state->remove<RegionState>(ReallocSym);
2816           break;
2817         default:
2818           assert(I.getData().Kind == OAR_FreeOnFailure);
2819         }
2820       }
2821     }
2822     state = state->remove<ReallocPairs>(I.getKey());
2823   }
2824 
2825   return state;
2826 }
2827 
2828 bool MallocChecker::mayFreeAnyEscapedMemoryOrIsModeledExplicitly(
2829                                               const CallEvent *Call,
2830                                               ProgramStateRef State,
2831                                               SymbolRef &EscapingSymbol) const {
2832   assert(Call);
2833   EscapingSymbol = nullptr;
2834 
2835   // For now, assume that any C++ or block call can free memory.
2836   // TODO: If we want to be more optimistic here, we'll need to make sure that
2837   // regions escape to C++ containers. They seem to do that even now, but for
2838   // mysterious reasons.
2839   if (!(isa<SimpleFunctionCall>(Call) || isa<ObjCMethodCall>(Call)))
2840     return true;
2841 
2842   // Check Objective-C messages by selector name.
2843   if (const ObjCMethodCall *Msg = dyn_cast<ObjCMethodCall>(Call)) {
2844     // If it's not a framework call, or if it takes a callback, assume it
2845     // can free memory.
2846     if (!Call->isInSystemHeader() || Call->argumentsMayEscape())
2847       return true;
2848 
2849     // If it's a method we know about, handle it explicitly post-call.
2850     // This should happen before the "freeWhenDone" check below.
2851     if (isKnownDeallocObjCMethodName(*Msg))
2852       return false;
2853 
2854     // If there's a "freeWhenDone" parameter, but the method isn't one we know
2855     // about, we can't be sure that the object will use free() to deallocate the
2856     // memory, so we can't model it explicitly. The best we can do is use it to
2857     // decide whether the pointer escapes.
2858     if (Optional<bool> FreeWhenDone = getFreeWhenDoneArg(*Msg))
2859       return *FreeWhenDone;
2860 
2861     // If the first selector piece ends with "NoCopy", and there is no
2862     // "freeWhenDone" parameter set to zero, we know ownership is being
2863     // transferred. Again, though, we can't be sure that the object will use
2864     // free() to deallocate the memory, so we can't model it explicitly.
2865     StringRef FirstSlot = Msg->getSelector().getNameForSlot(0);
2866     if (FirstSlot.endswith("NoCopy"))
2867       return true;
2868 
2869     // If the first selector starts with addPointer, insertPointer,
2870     // or replacePointer, assume we are dealing with NSPointerArray or similar.
2871     // This is similar to C++ containers (vector); we still might want to check
2872     // that the pointers get freed by following the container itself.
2873     if (FirstSlot.startswith("addPointer") ||
2874         FirstSlot.startswith("insertPointer") ||
2875         FirstSlot.startswith("replacePointer") ||
2876         FirstSlot.equals("valueWithPointer")) {
2877       return true;
2878     }
2879 
2880     // We should escape receiver on call to 'init'. This is especially relevant
2881     // to the receiver, as the corresponding symbol is usually not referenced
2882     // after the call.
2883     if (Msg->getMethodFamily() == OMF_init) {
2884       EscapingSymbol = Msg->getReceiverSVal().getAsSymbol();
2885       return true;
2886     }
2887 
2888     // Otherwise, assume that the method does not free memory.
2889     // Most framework methods do not free memory.
2890     return false;
2891   }
2892 
2893   // At this point the only thing left to handle is straight function calls.
2894   const FunctionDecl *FD = cast<SimpleFunctionCall>(Call)->getDecl();
2895   if (!FD)
2896     return true;
2897 
2898   // If it's one of the allocation functions we can reason about, we model
2899   // its behavior explicitly.
2900   if (MemFunctionInfo.isMemFunction(*Call))
2901     return false;
2902 
2903   // If it's not a system call, assume it frees memory.
2904   if (!Call->isInSystemHeader())
2905     return true;
2906 
2907   // White list the system functions whose arguments escape.
2908   const IdentifierInfo *II = FD->getIdentifier();
2909   if (!II)
2910     return true;
2911   StringRef FName = II->getName();
2912 
2913   // White list the 'XXXNoCopy' CoreFoundation functions.
2914   // We specifically check these before
2915   if (FName.endswith("NoCopy")) {
2916     // Look for the deallocator argument. We know that the memory ownership
2917     // is not transferred only if the deallocator argument is
2918     // 'kCFAllocatorNull'.
2919     for (unsigned i = 1; i < Call->getNumArgs(); ++i) {
2920       const Expr *ArgE = Call->getArgExpr(i)->IgnoreParenCasts();
2921       if (const DeclRefExpr *DE = dyn_cast<DeclRefExpr>(ArgE)) {
2922         StringRef DeallocatorName = DE->getFoundDecl()->getName();
2923         if (DeallocatorName == "kCFAllocatorNull")
2924           return false;
2925       }
2926     }
2927     return true;
2928   }
2929 
2930   // Associating streams with malloced buffers. The pointer can escape if
2931   // 'closefn' is specified (and if that function does free memory),
2932   // but it will not if closefn is not specified.
2933   // Currently, we do not inspect the 'closefn' function (PR12101).
2934   if (FName == "funopen")
2935     if (Call->getNumArgs() >= 4 && Call->getArgSVal(4).isConstant(0))
2936       return false;
2937 
2938   // Do not warn on pointers passed to 'setbuf' when used with std streams,
2939   // these leaks might be intentional when setting the buffer for stdio.
2940   // http://stackoverflow.com/questions/2671151/who-frees-setvbuf-buffer
2941   if (FName == "setbuf" || FName =="setbuffer" ||
2942       FName == "setlinebuf" || FName == "setvbuf") {
2943     if (Call->getNumArgs() >= 1) {
2944       const Expr *ArgE = Call->getArgExpr(0)->IgnoreParenCasts();
2945       if (const DeclRefExpr *ArgDRE = dyn_cast<DeclRefExpr>(ArgE))
2946         if (const VarDecl *D = dyn_cast<VarDecl>(ArgDRE->getDecl()))
2947           if (D->getCanonicalDecl()->getName().find("std") != StringRef::npos)
2948             return true;
2949     }
2950   }
2951 
2952   // A bunch of other functions which either take ownership of a pointer or
2953   // wrap the result up in a struct or object, meaning it can be freed later.
2954   // (See RetainCountChecker.) Not all the parameters here are invalidated,
2955   // but the Malloc checker cannot differentiate between them. The right way
2956   // of doing this would be to implement a pointer escapes callback.
2957   if (FName == "CGBitmapContextCreate" ||
2958       FName == "CGBitmapContextCreateWithData" ||
2959       FName == "CVPixelBufferCreateWithBytes" ||
2960       FName == "CVPixelBufferCreateWithPlanarBytes" ||
2961       FName == "OSAtomicEnqueue") {
2962     return true;
2963   }
2964 
2965   if (FName == "postEvent" &&
2966       FD->getQualifiedNameAsString() == "QCoreApplication::postEvent") {
2967     return true;
2968   }
2969 
2970   if (FName == "postEvent" &&
2971       FD->getQualifiedNameAsString() == "QCoreApplication::postEvent") {
2972     return true;
2973   }
2974 
2975   if (FName == "connectImpl" &&
2976       FD->getQualifiedNameAsString() == "QObject::connectImpl") {
2977     return true;
2978   }
2979 
2980   // Handle cases where we know a buffer's /address/ can escape.
2981   // Note that the above checks handle some special cases where we know that
2982   // even though the address escapes, it's still our responsibility to free the
2983   // buffer.
2984   if (Call->argumentsMayEscape())
2985     return true;
2986 
2987   // Otherwise, assume that the function does not free memory.
2988   // Most system calls do not free the memory.
2989   return false;
2990 }
2991 
2992 ProgramStateRef MallocChecker::checkPointerEscape(ProgramStateRef State,
2993                                              const InvalidatedSymbols &Escaped,
2994                                              const CallEvent *Call,
2995                                              PointerEscapeKind Kind) const {
2996   return checkPointerEscapeAux(State, Escaped, Call, Kind,
2997                                /*IsConstPointerEscape*/ false);
2998 }
2999 
3000 ProgramStateRef MallocChecker::checkConstPointerEscape(ProgramStateRef State,
3001                                               const InvalidatedSymbols &Escaped,
3002                                               const CallEvent *Call,
3003                                               PointerEscapeKind Kind) const {
3004   // If a const pointer escapes, it may not be freed(), but it could be deleted.
3005   return checkPointerEscapeAux(State, Escaped, Call, Kind,
3006                                /*IsConstPointerEscape*/ true);
3007 }
3008 
3009 static bool checkIfNewOrNewArrayFamily(const RefState *RS) {
3010   return (RS->getAllocationFamily() == AF_CXXNewArray ||
3011           RS->getAllocationFamily() == AF_CXXNew);
3012 }
3013 
3014 ProgramStateRef MallocChecker::checkPointerEscapeAux(
3015     ProgramStateRef State, const InvalidatedSymbols &Escaped,
3016     const CallEvent *Call, PointerEscapeKind Kind,
3017     bool IsConstPointerEscape) const {
3018   // If we know that the call does not free memory, or we want to process the
3019   // call later, keep tracking the top level arguments.
3020   SymbolRef EscapingSymbol = nullptr;
3021   if (Kind == PSK_DirectEscapeOnCall &&
3022       !mayFreeAnyEscapedMemoryOrIsModeledExplicitly(Call, State,
3023                                                     EscapingSymbol) &&
3024       !EscapingSymbol) {
3025     return State;
3026   }
3027 
3028   for (InvalidatedSymbols::const_iterator I = Escaped.begin(),
3029        E = Escaped.end();
3030        I != E; ++I) {
3031     SymbolRef sym = *I;
3032 
3033     if (EscapingSymbol && EscapingSymbol != sym)
3034       continue;
3035 
3036     if (const RefState *RS = State->get<RegionState>(sym))
3037       if (RS->isAllocated() || RS->isAllocatedOfSizeZero())
3038         if (!IsConstPointerEscape || checkIfNewOrNewArrayFamily(RS))
3039           State = State->set<RegionState>(sym, RefState::getEscaped(RS));
3040   }
3041   return State;
3042 }
3043 
3044 bool MallocChecker::isArgZERO_SIZE_PTR(ProgramStateRef State, CheckerContext &C,
3045                                        SVal ArgVal) const {
3046   if (!KernelZeroSizePtrValue)
3047     KernelZeroSizePtrValue =
3048         tryExpandAsInteger("ZERO_SIZE_PTR", C.getPreprocessor());
3049 
3050   const llvm::APSInt *ArgValKnown =
3051       C.getSValBuilder().getKnownValue(State, ArgVal);
3052   return ArgValKnown && *KernelZeroSizePtrValue &&
3053          ArgValKnown->getSExtValue() == **KernelZeroSizePtrValue;
3054 }
3055 
3056 static SymbolRef findFailedReallocSymbol(ProgramStateRef currState,
3057                                          ProgramStateRef prevState) {
3058   ReallocPairsTy currMap = currState->get<ReallocPairs>();
3059   ReallocPairsTy prevMap = prevState->get<ReallocPairs>();
3060 
3061   for (const ReallocPairsTy::value_type &Pair : prevMap) {
3062     SymbolRef sym = Pair.first;
3063     if (!currMap.lookup(sym))
3064       return sym;
3065   }
3066 
3067   return nullptr;
3068 }
3069 
3070 static bool isReferenceCountingPointerDestructor(const CXXDestructorDecl *DD) {
3071   if (const IdentifierInfo *II = DD->getParent()->getIdentifier()) {
3072     StringRef N = II->getName();
3073     if (N.contains_lower("ptr") || N.contains_lower("pointer")) {
3074       if (N.contains_lower("ref") || N.contains_lower("cnt") ||
3075           N.contains_lower("intrusive") || N.contains_lower("shared")) {
3076         return true;
3077       }
3078     }
3079   }
3080   return false;
3081 }
3082 
3083 PathDiagnosticPieceRef MallocBugVisitor::VisitNode(const ExplodedNode *N,
3084                                                    BugReporterContext &BRC,
3085                                                    PathSensitiveBugReport &BR) {
3086   ProgramStateRef state = N->getState();
3087   ProgramStateRef statePrev = N->getFirstPred()->getState();
3088 
3089   const RefState *RSCurr = state->get<RegionState>(Sym);
3090   const RefState *RSPrev = statePrev->get<RegionState>(Sym);
3091 
3092   const Stmt *S = N->getStmtForDiagnostics();
3093   // When dealing with containers, we sometimes want to give a note
3094   // even if the statement is missing.
3095   if (!S && (!RSCurr || RSCurr->getAllocationFamily() != AF_InnerBuffer))
3096     return nullptr;
3097 
3098   const LocationContext *CurrentLC = N->getLocationContext();
3099 
3100   // If we find an atomic fetch_add or fetch_sub within the destructor in which
3101   // the pointer was released (before the release), this is likely a destructor
3102   // of a shared pointer.
3103   // Because we don't model atomics, and also because we don't know that the
3104   // original reference count is positive, we should not report use-after-frees
3105   // on objects deleted in such destructors. This can probably be improved
3106   // through better shared pointer modeling.
3107   if (ReleaseDestructorLC) {
3108     if (const auto *AE = dyn_cast<AtomicExpr>(S)) {
3109       AtomicExpr::AtomicOp Op = AE->getOp();
3110       if (Op == AtomicExpr::AO__c11_atomic_fetch_add ||
3111           Op == AtomicExpr::AO__c11_atomic_fetch_sub) {
3112         if (ReleaseDestructorLC == CurrentLC ||
3113             ReleaseDestructorLC->isParentOf(CurrentLC)) {
3114           BR.markInvalid(getTag(), S);
3115         }
3116       }
3117     }
3118   }
3119 
3120   // FIXME: We will eventually need to handle non-statement-based events
3121   // (__attribute__((cleanup))).
3122 
3123   // Find out if this is an interesting point and what is the kind.
3124   StringRef Msg;
3125   std::unique_ptr<StackHintGeneratorForSymbol> StackHint = nullptr;
3126   SmallString<256> Buf;
3127   llvm::raw_svector_ostream OS(Buf);
3128 
3129   if (Mode == Normal) {
3130     if (isAllocated(RSCurr, RSPrev, S)) {
3131       Msg = "Memory is allocated";
3132       StackHint = std::make_unique<StackHintGeneratorForSymbol>(
3133           Sym, "Returned allocated memory");
3134     } else if (isReleased(RSCurr, RSPrev, S)) {
3135       const auto Family = RSCurr->getAllocationFamily();
3136       switch (Family) {
3137         case AF_Alloca:
3138         case AF_Malloc:
3139         case AF_CXXNew:
3140         case AF_CXXNewArray:
3141         case AF_IfNameIndex:
3142           Msg = "Memory is released";
3143           StackHint = std::make_unique<StackHintGeneratorForSymbol>(
3144               Sym, "Returning; memory was released");
3145           break;
3146         case AF_InnerBuffer: {
3147           const MemRegion *ObjRegion =
3148               allocation_state::getContainerObjRegion(statePrev, Sym);
3149           const auto *TypedRegion = cast<TypedValueRegion>(ObjRegion);
3150           QualType ObjTy = TypedRegion->getValueType();
3151           OS << "Inner buffer of '" << ObjTy.getAsString() << "' ";
3152 
3153           if (N->getLocation().getKind() == ProgramPoint::PostImplicitCallKind) {
3154             OS << "deallocated by call to destructor";
3155             StackHint = std::make_unique<StackHintGeneratorForSymbol>(
3156                 Sym, "Returning; inner buffer was deallocated");
3157           } else {
3158             OS << "reallocated by call to '";
3159             const Stmt *S = RSCurr->getStmt();
3160             if (const auto *MemCallE = dyn_cast<CXXMemberCallExpr>(S)) {
3161               OS << MemCallE->getMethodDecl()->getNameAsString();
3162             } else if (const auto *OpCallE = dyn_cast<CXXOperatorCallExpr>(S)) {
3163               OS << OpCallE->getDirectCallee()->getNameAsString();
3164             } else if (const auto *CallE = dyn_cast<CallExpr>(S)) {
3165               auto &CEMgr = BRC.getStateManager().getCallEventManager();
3166               CallEventRef<> Call = CEMgr.getSimpleCall(CallE, state, CurrentLC);
3167               const auto *D = dyn_cast_or_null<NamedDecl>(Call->getDecl());
3168               OS << (D ? D->getNameAsString() : "unknown");
3169             }
3170             OS << "'";
3171             StackHint = std::make_unique<StackHintGeneratorForSymbol>(
3172                 Sym, "Returning; inner buffer was reallocated");
3173           }
3174           Msg = OS.str();
3175           break;
3176         }
3177         case AF_None:
3178           llvm_unreachable("Unhandled allocation family!");
3179       }
3180 
3181       // See if we're releasing memory while inlining a destructor
3182       // (or one of its callees). This turns on various common
3183       // false positive suppressions.
3184       bool FoundAnyDestructor = false;
3185       for (const LocationContext *LC = CurrentLC; LC; LC = LC->getParent()) {
3186         if (const auto *DD = dyn_cast<CXXDestructorDecl>(LC->getDecl())) {
3187           if (isReferenceCountingPointerDestructor(DD)) {
3188             // This immediately looks like a reference-counting destructor.
3189             // We're bad at guessing the original reference count of the object,
3190             // so suppress the report for now.
3191             BR.markInvalid(getTag(), DD);
3192           } else if (!FoundAnyDestructor) {
3193             assert(!ReleaseDestructorLC &&
3194                    "There can be only one release point!");
3195             // Suspect that it's a reference counting pointer destructor.
3196             // On one of the next nodes might find out that it has atomic
3197             // reference counting operations within it (see the code above),
3198             // and if so, we'd conclude that it likely is a reference counting
3199             // pointer destructor.
3200             ReleaseDestructorLC = LC->getStackFrame();
3201             // It is unlikely that releasing memory is delegated to a destructor
3202             // inside a destructor of a shared pointer, because it's fairly hard
3203             // to pass the information that the pointer indeed needs to be
3204             // released into it. So we're only interested in the innermost
3205             // destructor.
3206             FoundAnyDestructor = true;
3207           }
3208         }
3209       }
3210     } else if (isRelinquished(RSCurr, RSPrev, S)) {
3211       Msg = "Memory ownership is transferred";
3212       StackHint = std::make_unique<StackHintGeneratorForSymbol>(Sym, "");
3213     } else if (hasReallocFailed(RSCurr, RSPrev, S)) {
3214       Mode = ReallocationFailed;
3215       Msg = "Reallocation failed";
3216       StackHint = std::make_unique<StackHintGeneratorForReallocationFailed>(
3217           Sym, "Reallocation failed");
3218 
3219       if (SymbolRef sym = findFailedReallocSymbol(state, statePrev)) {
3220         // Is it possible to fail two reallocs WITHOUT testing in between?
3221         assert((!FailedReallocSymbol || FailedReallocSymbol == sym) &&
3222           "We only support one failed realloc at a time.");
3223         BR.markInteresting(sym);
3224         FailedReallocSymbol = sym;
3225       }
3226     }
3227 
3228   // We are in a special mode if a reallocation failed later in the path.
3229   } else if (Mode == ReallocationFailed) {
3230     assert(FailedReallocSymbol && "No symbol to look for.");
3231 
3232     // Is this is the first appearance of the reallocated symbol?
3233     if (!statePrev->get<RegionState>(FailedReallocSymbol)) {
3234       // We're at the reallocation point.
3235       Msg = "Attempt to reallocate memory";
3236       StackHint = std::make_unique<StackHintGeneratorForSymbol>(
3237           Sym, "Returned reallocated memory");
3238       FailedReallocSymbol = nullptr;
3239       Mode = Normal;
3240     }
3241   }
3242 
3243   if (Msg.empty()) {
3244     assert(!StackHint);
3245     return nullptr;
3246   }
3247 
3248   assert(StackHint);
3249 
3250   // Generate the extra diagnostic.
3251   PathDiagnosticLocation Pos;
3252   if (!S) {
3253     assert(RSCurr->getAllocationFamily() == AF_InnerBuffer);
3254     auto PostImplCall = N->getLocation().getAs<PostImplicitCall>();
3255     if (!PostImplCall)
3256       return nullptr;
3257     Pos = PathDiagnosticLocation(PostImplCall->getLocation(),
3258                                  BRC.getSourceManager());
3259   } else {
3260     Pos = PathDiagnosticLocation(S, BRC.getSourceManager(),
3261                                  N->getLocationContext());
3262   }
3263 
3264   auto P = std::make_shared<PathDiagnosticEventPiece>(Pos, Msg, true);
3265   BR.addCallStackHint(P, std::move(StackHint));
3266   return P;
3267 }
3268 
3269 void MallocChecker::printState(raw_ostream &Out, ProgramStateRef State,
3270                                const char *NL, const char *Sep) const {
3271 
3272   RegionStateTy RS = State->get<RegionState>();
3273 
3274   if (!RS.isEmpty()) {
3275     Out << Sep << "MallocChecker :" << NL;
3276     for (RegionStateTy::iterator I = RS.begin(), E = RS.end(); I != E; ++I) {
3277       const RefState *RefS = State->get<RegionState>(I.getKey());
3278       AllocationFamily Family = RefS->getAllocationFamily();
3279       Optional<MallocChecker::CheckKind> CheckKind = getCheckIfTracked(Family);
3280       if (!CheckKind.hasValue())
3281          CheckKind = getCheckIfTracked(Family, true);
3282 
3283       I.getKey()->dumpToStream(Out);
3284       Out << " : ";
3285       I.getData().dump(Out);
3286       if (CheckKind.hasValue())
3287         Out << " (" << CheckNames[*CheckKind].getName() << ")";
3288       Out << NL;
3289     }
3290   }
3291 }
3292 
3293 namespace clang {
3294 namespace ento {
3295 namespace allocation_state {
3296 
3297 ProgramStateRef
3298 markReleased(ProgramStateRef State, SymbolRef Sym, const Expr *Origin) {
3299   AllocationFamily Family = AF_InnerBuffer;
3300   return State->set<RegionState>(Sym, RefState::getReleased(Family, Origin));
3301 }
3302 
3303 } // end namespace allocation_state
3304 } // end namespace ento
3305 } // end namespace clang
3306 
3307 // Intended to be used in InnerPointerChecker to register the part of
3308 // MallocChecker connected to it.
3309 void ento::registerInnerPointerCheckerAux(CheckerManager &mgr) {
3310   MallocChecker *checker = mgr.getChecker<MallocChecker>();
3311   checker->ChecksEnabled[MallocChecker::CK_InnerPointerChecker] = true;
3312   checker->CheckNames[MallocChecker::CK_InnerPointerChecker] =
3313       mgr.getCurrentCheckerName();
3314 }
3315 
3316 void ento::registerDynamicMemoryModeling(CheckerManager &mgr) {
3317   auto *checker = mgr.registerChecker<MallocChecker>();
3318   checker->MemFunctionInfo.ShouldIncludeOwnershipAnnotatedFunctions =
3319       mgr.getAnalyzerOptions().getCheckerBooleanOption(checker, "Optimistic");
3320 }
3321 
3322 bool ento::shouldRegisterDynamicMemoryModeling(const CheckerManager &mgr) {
3323   return true;
3324 }
3325 
3326 #define REGISTER_CHECKER(name)                                                 \
3327   void ento::register##name(CheckerManager &mgr) {                             \
3328     MallocChecker *checker = mgr.getChecker<MallocChecker>();                  \
3329     checker->ChecksEnabled[MallocChecker::CK_##name] = true;                   \
3330     checker->CheckNames[MallocChecker::CK_##name] =                            \
3331         mgr.getCurrentCheckerName();                                           \
3332   }                                                                            \
3333                                                                                \
3334   bool ento::shouldRegister##name(const CheckerManager &mgr) { return true; }
3335 
3336 REGISTER_CHECKER(MallocChecker)
3337 REGISTER_CHECKER(NewDeleteChecker)
3338 REGISTER_CHECKER(NewDeleteLeaksChecker)
3339 REGISTER_CHECKER(MismatchedDeallocatorChecker)
3340